The maximum concentration of alcohol in beverages that are naturally fermented is:
1. 5 - 10%
2. 10 - 15%
3. 20 - 25%
4. 45 - 50%
The virus shown here is a causative agent of :
1. Intestinal infections
2. Respiratory infections
3. CNS infections
4. Genito-urinary infections
Besides helper T cells, what are two other types of cells that HIV infects?
(1) macrophages and brain cells
(2) B cells and liver cells
(3) plasma cells and neutrophils
(4) cytotoxic T cells and brain cells
When searching for a donor for an organ transplant, doctors try to match the __________ of the donor and recipient as closely as possible.
(2) blood type
(3) MHC proteins
In a series of immune system experiments, the thymus glands were removed from baby mice. Which of the following would you predict as a likely result?
(1) The mice suffered from numerous allergies.
(2) The mice never developed cancerous tumors.
(3) The mice suffered from autoimmune diseases.
(4) The mice readily accepted tissue transplants.
The antigen-binding sites of an antibody molecule are formed from the molecule's variable regions. Why are these regions described as variable?
(1) They can change their shapes to fit different antigens.
(2) They change their shapes when they bind to an antigen.
(3) Their specific shapes are unimportant.
(4) The amino acid sequences of these regions vary widely among antibodies from different B cells.
Chemicals produced by virus-infected cells that alert neighboring cells to prepare a defense are called:
For the stability of the organic compounds, Oparin opined that probably:
1. UV radiation never reached the surface of the primeval Earth
2. the primeval Earth was in a molten state
3. the primeval Earth atmosphere was reducing rather than oxidizing
4. plenty of energy sources were available for chemical reactions to occur
For origin of life, which of the following is not a precondition, needed to be fulfilled by the protobionts under consideration?
1. They should have been able to totally isolate themselve from the general environment
2. They should have been able to replicate
3. They should have acquired a perpetual source of energy
4. Their replication should have been subject to error via mutation
The first genetic code of life was based on:
Which of the following is not a precondition for Hardy-Weinberg Equilibrium?
1. The population should be large
2. The mating should be assortative
3. There is no gene flow into or out of the population
4. All offspring should be equally fertile.
What is genetic equilibrium?
1. When all the alleles of a gene are present in a population in equal frequencies
2. When the number of heterozygotes in a population are equal to the number of either of the homozygote.
3. When the number of heterozygotes in a population are equal to the number of either of the homozygote.
4. When the frequency of particular genes or alleles remain constant in a population through generations
Which of the following is the most important precondition for speciation to occur?
(1) Reproductive isolation
(2) A crash of the population size
(3) Adaptive radiation
(4) Random mating
Some of the marsupials of Australia resemble equivalent placental mammals that live in similar habitats of other continents. This is an example of:
1. Convergent evolution
2. Divergent evolution
3. Saltatory evolution
4. Adaptive radiation
The only evolutionary agent that produces adaptive evolutionary changes is :
(1) Nonrandom mating
(3) Genetic drift
(4) Natural selection
A population of an animal is hunted down to only 20 organisms. Later the number is restored to 10,000 organisms, but the variations in this population are highly reduced. This is called:
1. Founder Effect
2. Bottleneck effect
3. Edge effect
What is the half life of U238, the radioactive isotope of uranium?
(1) 4500 years
(2) 4.5 million years
(3) 45 million years
(4) 4.6 billion years
The earliest known members of the horse family belong to the genus:
In a population of red (dominant) and white flowers, the frequency of red flowers is 91 %. What is the frequency of the red allele?
(1) 9 %
(2) 30 %
(3) 91 %
(4) 70 %
............... operates to eliminate intermediate phenotypes.
(1) Directional selection
(2) Disruptive selection
(3) Stabilizing selection
(4) Random chance
The best test of relatedness of two species is in the similarity of their :
(2) DNA and Proteins
(4) Courtship behavior
The selecting agent in industrial melanism was :
(2) toxins from smoke
(4) tree bark
Many bacteria are now resistant to penicillin, because:
(1) penicillin causes gene mutations, some of which are beneficial
(2) previously resistant forms survived and reproduced better than non-resistant forms
(3) the hospital environment inhibits competition among bacteria
(4) penicillin triggers the synthesis of resistant proteins
The unit of evolution is now known to be the:
A change in allele frequency within a population, over a succession of generations, is called:
(1) microevolution, or adaptive evolution
(2) macroevolution, or speciation
(4) phylogenetic evolution
A plant population that reproduces by self - pollination is an extreme example of :
(1) the bottleneck effect
(2) the founder effect
(3) rapid gene flow
(4) assortative mating
Natural selection is best defined as occurring when the environment causes :
(1) differential success in reproduction
(2) differential mortality
(3) assortative mating
(4) a reduced gene pool
People who carry an allele for normal hemoglobin and an allele for sickle cell are resistant to malaria. They are examples of:
1. heteozygote advantage
2. extreme diploidy
4. recessive superiority
A deleterious allele decreases more rapidly in frequency if it is:
(1) recently mutated
Natural selection acts on an organism’s:
(1) dominant alleles
(2) recessive, homozygous alleles
(4) combined genotype
Tobacco plant has been made resistant to the tobacco mosaic virus by :
(1) introducing T-DNA of Agrobacterium
(2) introducing a gene for virus coat protein
(3) introducing meristematic activity in somatic cells
(4) applying newer generation pesticides to the crops
Damage to thymus in a child may lead to
1. A reduction in haemoglobin content of blood
2. A reduction in stem cell production
3. Loss of antibody mediated immunity
4. Loss of cell mediated immunity
Which one of the following depresses brain activity and produces feelings of calmness, relaxation and drowsiness -
AIDS is caused by HIV that principally infects
1. Activator B cells
2. T4 lymphocytes
3. Cytotoxic T cells
4. All lymphocytes
The large vessels for growing microbes on an industrial scale are called
1. Petri dish
3. biogas vessel
BOD of waste water is estimated by measuring the amount of
1. total organic matter
2. biodegradable organic matter
3. oxygen evolution
4. oxygen consumption
Big holes in Swiss cheese are made by a
2. bacterium that produces methane gas
3. bacterium producing a large amount of carbon dioxide
4. fungus that releases a lot of gases during its metabolic activities
Common cold is not cured by antibiotics because it is
1. caused by a Gram-negaive bacterium
2. not an infectious disease
3. viral disease
4. caused by a Gram-positive bacterium
Which of the following represents the form of Plasmodium that is released from the erythrocyte by lysis?
Dysarthria on consumption of alcohol is due to the fact that alcohol affects:
4. Medulla oblangata
Which disease has been completely eradicated?
Influenza viruses are classified into groups based on the _______ antigens of their protein coats.
Infection with HIV will result in a depletion of
1. CD1+ cells.
2. CD2+ cells.
3. CD3+ cells.
4. CD4+ cells.
Prion diseases share important clinical, neuropathological, and cell biological features with:
2. Creutzfeldt-Jakob disease
4. Alzheimer's disease
At the time early life first formed on Earth, the atmosphere could best be described as:
3. rich in oxygen
4. low in hydrogen gas
Which of the following statements is TRUE?
1. Prokaryotes evolved before eukaryotes.
2. Eukaryotes evolved before prokaryotes.
3. Prokaryotes and eukaryotes evolved at approximately the same time.
4. It is unclear whether prokaryotes or eukaryotes evolved first
Reproductive isolation in sympatric speciation develops without a:
1. Geographic barrier
2. Barrier to gene flow
3. Change in chromosome number
4. Barrier to mating
Distantly related organisms with similar traits have experienced:
2. Convergent evolution
3. Divergent evolution
4. Parallel evolution
Natural selection acts on an organism's :
1. Dominant alleles
2. Recessive alleles
4. Combined genotype
Disruptive selection favors:
1. Both extreme forms of a trait
2. Intermediate forms of a trait
3. One of the extremes of a trait
4. Environmental differences
A deleterious allele decreases more rapidly in frequency if it is:
1. Recently mutated
The extint reptile group from which mammals directly evolved is:
Which one of the following would cause the Hardy-Weinberg principle to be inaccurate?
1. The size of the population is very large.
2. Individuals mate with one another at random.
3. Natural selection is present.
4. There is no source of new copies of alleles from outside the population.
Which of the following ideas was developed by Thomas Malthus?
1. Peppered moths living near English industrial cities provide a good example of evolution.
2. The diversity of Galápagos finch species is the result of natural selection.
3. Living things often produce far more offspring than are needed to maintain their numbers.
4. Reproductive isolation is pre-condition for speciation
Which of the following is not a vector borne disease?
1. African sleeping sickness
Adaptive immunity depends on:
1. traits common to groups of pathogens.
2. pathogen-specific recognition.
3. maternal provision of antibodies to offspring.
4. having exhausted all options for innate immunity responses.
A patient who can produce antibodies against some bacterial pathogens, but not against viral infections, probably has a disorder in his
1. B cells.
2. plasma cells.
3. natural killer cells.
4. T cells.
Pyrethrin is obtained from:
1. Dahlia pinnata
2. Azadirachta indica
3. Mangifera indica
4. Chrysanthemum cinerarifolium
Match the items in Column ‘A’ and Column ‘B’ and choose correct answer.
Column A Column B
i. Lady bird a. Methanobacterium
ii. Mycorrhiza b. Trichoderma
iii. Biological control c. Aphids
iv. Biogas d. Glomus
The correct answer is
1. i b, ii d, iii c, iv a
2. i c, ii d, iii b, iv a
3. i d, ii a, iii b, iv c
4. i c, ii b, iii a, iv d
The bacteria and mould involved in the work of Alexander Fleming are :-
1. Staphylococci and Penicillium chrysogenum
2. Streptococci and Penicillium chrysogenum
3. Staphylococci and Penicillium notatum
4. Streptococci and Penicillium notatum
Name the product formed by Trichoderma polysporum and give its use.
1. Statins which are used as blood cholesterol lowering agent.
2. Cyclosporin A that is used as immunosuppressive agent.
3. Statins which are used as clot buster.
4. Cyclosporin A that is used to inhibit the enzyme responsible for cholesterol synthesis.
The causative organism of African sleeping sickness is:
1. Glossina palpalis
4. Giardia lamblia
Which of the following is mismatched?
1. B cells: can be activated to produce antibodies
2. Helper T cells: directly target and kill cancer cells
3. Cytotoxic T cells: carry out cellular immune responses
4. Suppressor T cells: release inhibitory cytokines to dampen the immune response
Which type of molecule is produced by viral- infected cells to communicate to non-infected cells of the presence of a virus?
The ineffectiveness of many antibiotics today is most closely associated with:
2. F plasmids
3. R plasmids
4. Catabolite repression
Identify the incorrect statement:
(i) Bacillus thuringiensisare available in sachets as dried spores which are mixed with kerosene and sprayed on to vulnerable plants
(ii) B.thuringiensis are used to control butterfly caterpillars, but leave other insects unharmed
(iii) The toxin of B.thuringiensis is released in the blood of larvae and the larvae get killed
(iv) By the development of methods of genetic engineering B.thuringiensis toxin genes have been introduced into plants
1. (i) and (ii)
2. (ii) and (iii)
3. (i) and (iii)
4. (ii) and (iv)
Gynogenic haploids are produced by using
1. Unfertilised ovules
2. Fertilised ovules
3. Somatic embryo
4. Shoot apex
Pomato is an intergeneric somatic hybrid of
1. Potato and Brinjal
2. Potato and Tomato
3. Tomato and Brinjal
4. Potato and Tobacco
In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by
Select the incorrect match
1. Protina variety : Maize
2. Triticum aestivum : Bread wheat
3. Mexican wheat : HUW - 468
4. Atlas 66 : Used as donor for improving cultivated wheat
' Sonalika and Kalyan sona ' are high yielding varities of
' Saccharum barberi ' was originally grown in which part of India ?
1. North India
2. South India
3. Western India
4. Eastern India
Tobacco mosaic and turnip mosaic diseases are caused by
Which of the following variety is resistant to disease 'hill bunt' ?
2. Pusa Sadabahar
3. Pusa Komal
4. Pusa Sawani
Isolated protoplasts from two different varieties of plant can be fused to form hybrid protoplast. which can be grown into new plant. These hybrids are called as
2. protoplasts hybrid
3. somatic hybrid
4. none of these
Which phytohormone promotes shoot culture ?
1. Napthalene acetic acid
2. Benzyl amino purine
3. Indole -3- acetic acid
4. Gibberellic acid
How many given parts of plants are used as explants to produce virus free new plant
A. Apical meristem
B. Lateral meristem of dicot plants
C. Intercalary meristem
D. Xylem of any plants
E. Parenchyma of stem
1. A and B
2. A and C
3. A, C and D
4. All of these
To obtain microbial product at industrial scale which equipment is used.
1. Auto clave.
3. Laminar flow.
The microbial biocontrol agent with species-specific narrow spectrum insecticidal application is
In the given diagram the gas X can be:
1. Hydrogen sulfide
2. Carbon monoxide
During sewage treatment, biogases are produced which include :
1. Methane,oxygen, hydrogen sulphide
2. Hydrogen sulphide, methane, sulphur dioxide
3. Methane, hydrogen sulphide, carbon dioxide
4. Hydrogen sulphide, nitrogen, methane
All are correct w.r.t BOD (Biochemical oxygen Demand), except
1. It refers to the amount of oxygen that would be consumed if all the organic matter in one liter of water were oxidized by bacteria
2. The BOD test is a measure of the organic matter present in the water
3. The greater the BOD of waste water, less is its polluting potential
4. Waste water is treated till BOD is reduced significantly
The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the ones categorized as
1. Chemosynthetic autotrophs
2. Heterotrophic bacteria
What are flocs?
(1) Masses of anaerobic bacteria
(2) Masses of aerobic fungi only
(3) Masses of anaerobic bacteria and fungi
(4) Masses of aerobic bacteria associated with fungal filaments
The most common substrate used in distelleries for the production of ethanol is
(2) Corn meal
(3) Soya meal
(4) Ground gram
Select the correct statement from the following
(1) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria
(2) Biogas is produced by the activity of aerobic bacteria on animal waste
(3) Methanobacterium is an aerobic bacterium found in rumen of cattle
(4) Biogas, commonly called gobar gas is pure methane
(1) Live microbial food supplement
(2) Safe antibiotics
(3) Cancer inducing microbes
(4) New kind of food allergens
One of the major difficulties in the biological control of insect/pest is that
(1) The method is less effective as compared with the use of insecticides
(2) The practical difficulty of introducing the predator to specific areas
(3) The predator develops a preference to other deits and may itself become a pest
(4) The predator does not always survive when transferred to a new environment
Which one of the following helps in absorption of phosphorus from soil by plants ?
An organism used as a biofertilizer for raising soyabean crop is
Which set of reagents will produce freon (CCl2F2)?
1. C + F2 + Cl2
2. CH3Cl + F2
3. CCl4 + HF
4. CCl4 + F2
Vicinal and geminal dihalides can be distinguished by:-
1. KOH (aq)
3. Zn dust
4. None of the above
The halide which undergoes nucleophilic substitution most readily is:
Which would be least reactive towards bromine?
Dunstan’s test is used for identification of:
(4) carbonyl compound
The toxicity order for CH3OH, C2H5OH and C3H7OH is:
(1) C2H5OH < CH3OH < C3H7OH
(2) C3H7OH < C2H5OH < CH3OH
(3) C2H5OH < C3H7OH < CH3OH
(4) CH3OH < C2H5OH < C3H7OH
The organic product in the reaction is:
+ one equivalent of HI Product
Ether fire can be extinguished by:
(4) all of these
Purity of ether before using it as anaesthetic agent is tested by :-
1. KI + starch
4. none of these
C2H5OH cannot be dried by anhydrous CaCl2, because:
(1) C2H5OH is soluble in water
(2) explosion takes place
(3) C2H2OH reacts with CaCl2
(4) none of the above
The alcohol that forms fats with fatty acids is:
The explosive nitroglycerine is:
(1) a soap
(2) a salt
(3) an ester
(4) a complex compound
Denatured spirit is mainly used as a:
(1) good fuel
(3) solvent in preparing varnishes
(4) material in the preparation of oil
A characteristic group test for phenolic gp. is:
1. Liebermann's nitroso reaction
2. coupling with diazonium salt
3. aqueous FeCl3
4. all of the above
An organic compound C7H8O is neither soluble in NaOH nor gives blue colour with FeCl3, is:
(4) none of these
The electrophile involved in the above reaction is:
1. dichloromethyl cation ()
2. dichlorocarbene (:CCl2)
3. trichloromethyl anion ()
4. formyl cation ()
An unknown alcohol is treated with the “Lucas reagent” to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts the fastest and by what mechanism:
1. secondary alcohol by SN2
2. tertiary alcohol by SN2
3. secondary alcohol by SN1
4. tertiary alcohol by SN1
Phenyl ethyl ether with concentrated hydrobromic acid on boiling yields:-
1. Phenol and ethyl bromide
2. Bromobenzene and ethanol
3. Phenol and ethane
4. Bromobenzene and ethane
The compound that does not react with sodium is-
2. CH3 —O—CH3
The correct order of reactivity of PhMgBr with,
A distinctive and characteristic functional group in fat is-
1. Keto group
2. Ester group
3. Amine group
4 None of the above
a-chloropropionic acid on treatment with alcoholic KOH followed by acidification gives-
4. None of the above
Wacker method is used to convert alkene into corresponding ......... using PdCl2.
The compound that forms Zwitter ions is -
2. Salicylic acid
3. Phthalic acid
4. Sulphanilic acid
The IUPAC name of is:
(1) 6-oxohexanoic acid
(2) hexan-1-al-6-oic acid
(3) 1-aldo-hexanoic acid
(4) 6-aldo-hexan-1-oic acid
When is reduced by LiAlH4, the compound obtained is :
The major products(s) of following reaction is (are):
A compound A when reacted with PCl5 and then with ammonia gave B. B when treated with bromine and caustic potash produced C. C on treatment with NaNO2 and HCl at C and on boiling produced ortho-cresol. Compound A is-
1. o-Toluic acid
4. m-Toluic acid
AgNO3(aq) gives yellow ppt. with:
(1) KIO3 (aq)
(2) KI (aq)
Which is the product formed when cyclohexanone undergoes aldol condensation followed by heating ?
In the given reaction
the product P is
Consider the reaction
CH3CH2CH2Br + NaCN CH3CH2CH2CN + NaBr
This reaction will be the fastest in
3. N,N'-dimethylformamide (DMF)
can be classified as
1. Alcohol formation reaction
2. Dehydration reaction
3. Williamson alcohol synthesis reaction
4. Williamson ether synthesis reaction
The product formed by the reaction of an aldehyde with a primary amine is
2. Carboxylic acid
3. Aromatic acid
4. Schiff base
A single compound of the structure is obtained from ozonolysis of which of the following cyclic compounds?
An esters that gets hydrolyzed most easily under alkaline conditions is -
Reaction of phenol with chloroform in the presence of dilute sodium hydroxide finally
introduces, which one of the following functional group?
Which of the following is not the product of dehydration of
Among the following sets of reactants which one produces anisole ?
1. CH3CHO; RMgX
2. C6H5OH; NaOH; CH3l
3. C6H5OH; neutral FeCl3
4. C6H5-CH3; CH3COCl; AlCl3
H2COH.CH2OH on heating with periodic acid gives :-
In SN2 substitution reaction of the type
Which one of the following has the highest relative rate ?
Which of the following compounds will be formed?
Consider the following compounds :
The Correct decreasing order of their reactivity towards hydrolysis is :
(1) (ii) > (iv) > (iii) > (i)
(2) (i) > (ii) > (iii) > (iv)
(3) (iv) > (ii) > (i) > (iii)
(4) (ii) > (iv) > (i) > (iii)
The major organic product in the reaction, CH3 — O — CH(CH3)2 + HI Product is :
(3) CH3O CI(CH3)2
Ethylene oxide when treated with Grignard reagent yields :
(1) secondary alcohol
(2) tertiary alcohol
(3) cyclopropyl alcohol
(4) primary alcohol
A hollow conducting sphere is placed in an electric field produced by a point charge placed at P as shown in figure. Let ,, be the potential at points A, B and C respectively. Then:
The concentric spheres are of radii and . The outer sphere is given a charge q. The charge q' on the inner sphere will be (inner sphere is grounded)
In a uniform electric field, the potential is 10V at the origin of coordinates, and 8V at each of the points (1, 0, 0), (0, 1, 0) and (0, 0, 1). The potential at the point (1, 1, 1) will be
In a regular polygon of n sides, each corner is at a distance r from the centre. Identical charges are placed at (n-1) corners. At the centre, the intensity is E and the potential is V. The ratio V/E has magnitude
There are four concentric shells A, B, C and D of radii a, 2a, 3a, and 4a respectively. Shells B and D are given charges +q and -q respectively. Shell C is now earthed. The potential difference is:
A parallel plate capacitor is made by stacking n equally spaced plates connected alternately. If the capacitance between any two plates is C, then the resulting capacitance is:
A metal ball of radius R is placed concentrically inside a hollow metal sphere of inner radius 2R and outer radius 3R. The ball is given a charge +2Q and the hollow sphere a total charge -Q. The electrostatic potential energy of this system is:
A proton is first placed at A and then at B between the two plates of a parallel plate capacitor charged to a P.D. of V volt as shown. Then force on proton at A is-
(1) More than at B
(2) Less than at B
(3) Equal to that at B
(4) Nothing can be said
A long, hollow conducting cylinder is kept coaxially inside another long, hollow conducting cylinder of larger radius. Both the cylinders are initially electrically neutral.
(1) A potential difference appears between the two cylinders when a charge density is given to the inner cylinder.
(2) A potential difference appears between the two cylinders when a charge density is given to the outer cylinder.
(3) No potential difference appears between the two cylinders when a uniform line charge is kept along the axis of the cylinders
(4) No potential difference appears between the two cylinders when same charge density is given to both the cylinders.
The electric potential at a point due to an electric dipole will be:
Two batteries, one of emf 18 volts and internal resistance 2Ω and the other of emf 12 volt and internal resistance 1Ω, are connected as shown. The voltmeter V will record a reading of.
1. 18 volt
2. 30 volt
3. 14 volt
4. 15 volt
An electron moves in a circular orbit with a uniform speed v. It produces a magnetic field B at the centre of the circle. The radius of the circle is proportional to :
A 5-ampere fuse wire can withstand a maximum power of 1 watt in the circuit. The resistance of the fuse wire is :
1. 5 ohm
2. 0.04 ohm
3. 0.2 ohm
4. 0.4 ohm
A very long straight wire carries a current I. At the instant when a charge +Q at point P has velocity , as shown, the force on the charge is-
1. Along ox
2. Opposite to oy
3. Along oy
4. Opposite to ox
When a wire of uniform cross-section a, length l and resistance R is bent into a complete circle, resistance between any two of diametrically opposite points will be -
A coil in the shape of an equilateral triangle of side l is suspended between the pole pieces of a permanent magnet such that is in plane of the coil. If due to a current i in the triangle a torque acts on it, the side l of the triangle is-
For the network shown in the figure the value of the current, I (in Ampere) is:
Choose the only false statement from the following-
1. The resistivity of a semiconductor increases with increase in temperature
2. Substances with energy gap of the order of 10eV are insulators.
3. In conductors the valence and conduction bands may over lap
4. The conductivity of a semiconductor increases with increases in temperature.
A beam of alpha particles passes without deflection through crossed electric and magnetic field with Newton per Coulomb and . Their speed in metre per sec is
In the shown part of circuit potentials of points A, B and C and capacitance of capacitors are shown. Potential of point P is -
In the shown arrangement capacitance of each capacitor is C and emf of the cell is . If switch S is closed, then amount of charge flown through the switch is
Voltage drop across the terminals of a cell of EMF 2V is 1V when 2 A current is drawn from it. Internal resistance of the cell is?
Ohm's law is true for which of the following?
1. Semiconductors only
2. Metallic conductors only
3. For all the conductors
4. For superconductors only
Maximum voltage which can be applied across a resistor is
1. 81 volt
2. 16.2 volt
3. 9 volt
4. 40.5 volt
Two charged particles having charges q and mass m are moving on circular paths in same uniform magnetic field with speed v and 2v. Ratio of their angular velocities are
When current flows in steady state in the wire whose area of cross-section decreases as shown. Which of the following is incorrect?
1. Drift speed increases in the direction of current.
2. Electric field decreases in the direction of current.
3. Electric Potential decreases in the direction of current.
4. Current density increases in the direction of current.
For what value of the resistance X, the reading of ammeter will be zero?
What is the ratio of the readings of the voltmeter, V1 and V2 in the network shown below?
1. 1 : 2
2. 2 : 3
3. 3 : 1
4. 1 : 1
A wire of length l and carrying current i is folded to form double circular loop. The magnetic field at the centre is
A proton and an -particle enter with same momentum in a transverse uniform magnetic field. The ratio of the radii of curvature of their circular path will be
1. 1 : 2
2. 2 : 1
3. 3 : 2
4. 1 : 1
A small circular flexible loop of wire of radius r carries a current I. It is placed in a uniform magnetic field B. The tension in the loop will be doubled if:-
1. B is doubled.
2. I is halved.
3. r is halved.
4. Both B and r are doubled.
The magnitude of magnetic moment of the current loop shown in the figure is :-
4. None of these
Two concentric, thin metallic spheres of radii and bear changes and respectively. Then the potential at distance r between and will be
Find equivalent capacitance between X and Y if each capacitor is .
Maximum charge stored on a metal sphere of radius 15 cm may be . The potential energy of the sphere in this case is-
1. 9.67 J
2. 0.25 J
3. 3.25 J
4. 1.69 J
Resistance of a material at temperature . Here is the temperature at . The temperature coefficient of resistance at temperature t is -
Three voltmeters A, B and C having resistance R, 1.5 R and 3R, respectively, are connected as shown. When some potential difference is applied between X and Y, the voltmeter readings are and respectively. Then -
An electric bulb rated for 500W at 100V is used in a circuit having a 200V supply. The resistance R that must be put in series with the bulb, so that the bulb draws 500W is -
The length of a potentiometer wire is l. A cell of emf E is balanced at a length l/3 from the positive end of the wire. If the length of the wire is increased by l/2. At what distance will be the same cell give a balance point.
A magnet of moment M is lying in a magnetic field of induction B. is the work done in turning it from to and is the work done in turning it from to . Then -
A straight conductor of mass m and carrying a current i is hinged at one end and placed in a plane perpendicular to the magnetic field of intensity B as shown in the figure. At any moment if the conductor is let free, then the initial angular acceleration of the conductor will be (neglect gravity):-
Adjoining figure shows a rectangular loop of conductor carrying a current i. The length and breadth of the loop are respectively a and b. The magnetic field at the centre of loop is:-
As shown in the figure, P and Q are two coaxial conducting loops seperated by some distance. When the switch S is closed, a clockwise current flows in P (as seen by E) and an induces current flows in Q. The switch remains closed for a long time. Now S is opened, a current flows in Q. Then the directions of and (as seen by E) are:-
1. Respectively clockwise and anticlockwise.
2. Both clockwise
3. Both anticlockwise
4. Respectively anticlockwise and clockwise.
A particle with charge Q, moving with a momentum p, enters a unifrom magnetic field normally. The magnetic fied has magnitude B and is confined to a region of width d, where . The particle is deflected by an angle in crossing field. Then :
Five parallel infinite wires are placed at the vertices of a regular pentagon. Four wires carry current each while the fifth wire carries current 3 as shown. The resultant magnetic field at the centre O is :