Three electric bulbs of rating 60 W each are joined in series and then connected to electric mains. The power consumed by these three bulbs will be
1. 180 W
2. 60 W
3. 20 W
4. W
A current of 2 A passing through conductor produces 80 J of heat in 10 seconds. The resistance of the conductor is
1.
2.
3.
4.
If electrons are removed from a neutral body, the change acquired by the body is
1.
2.
3.
4.
A 220 V, 1000 W bulb is connected across a 110 V mains supply. The power consumed will be
1. 1000 W
2. 750 W
3. 500 W
4. 250 W
The resistance of a straight conductor is independent of
1. temperature
2. material
3. cross-sectional area
4. shape of cross-section
If in the ircuit, p[ower dissipation is 150 W, then R is
1.
2.
3.
4.
If and are the resistance of filaments of a 400 W and a 200 W lamp, designed to operate on the same voltage, then
1.
2.
3.
4.
The equivalent resistance between the points A and B as shown in the figure is
1.
2.
3.
4.
In a metallic conductor, electric current trought to be due to the movement of
1. ions
2. amperes
3. electrons
4. protons
A current of 4.8 A is flowing in a conductor. The number of electrons passing per second through the conductor will be
1.
2.
3.
4.
The V-I characteristics of four circuit elements are shown below. Whihc among the following is an ohic conductor?
1.
2.
3.
4.
In case of four wires of same material, the resistance will be minimum when its lwngth and diameters are respectively
1. L and D
2. 2L and D
3. and 2D
4. 2L and
A piece of resistance wire has resistance of . Its diameter is doubled. Now its resistance will be.
1.
2.
3.
4.
The resistance of the metallic conductors
1. increases with rise in temperature
2. decreases with rise in temperature
3. remains unchanged with change in temperature.
4. becomes zero at very high temperature.
Specific resistance is numerically equal to the resistance offered by
1. 1 cm length of a conductor
2. a conductor of unit cross-section
3. 1 cm length of conductor of 1 of cross-section
4. of a conductor
Two resistances are connected in parallel and a current is sent through the combination. The current divides itself
1. in the inverse ratio of resistance
2. in the direct ratio of resistance
3. equally in both the resistance
4. in none of the above manner
Given three equal resistors, how many different combinations of these three resistances can be made?
1. six
2. five
3. four
4. three
10,000 alpha-particles per minute are passing through a straighttube of radius r. The resulting electric current is approximately
1.
2.
3.
4.
Two conductor of resistance 2R and R are connected in series in a battery circuit. The ratio of heat developed in them is
1. 2:1
2. 1:2
3. 1:3
4. 1:4
1 volt=.............
1.
2.
3.
4. 1 joule coulumb
Two resistances are connected in series and then in parallel. The ratio of the effective resistance of series and parallel combination of resistance is
1. 2:9
2. 9:2
3. 3:1
4. 1:2
A current of 0.5 A passes through a conductor in 2 s. How many electrons flow through the conductor from its one to the other end during this interval of time?
1.
2.
3.
4.
If the length of a conductor having resistivity os doubled, its new resistivity will be
1.
2.
3.
4.
Calculate the length of aluminium wire of area of cross-section 1 whose resistance is . Given, resistivity of aluminium is
1. 60 mm
2. 60 cm
3. 60 m
4. 6 m
A current of 0.1 A flows through a conductor of resistance . The potential difference across the ends of the conductor is
1. 10 V
2. 100 V
3. 1 V
4. 0.1 V
The amount of heat produced in a conductor is
1. directly proportional to the current flowing through it
2. inversely proportional to the current flowing through it
3. directly proportional to the square of the current flowing through it
4. inversely proportional to the square of current flowing through it.
h1orse power is equal to
1. 700 W
2. 726 W
3. 736 W
4. 746 W
The amount of heat energy produced in 3 minutes by an electric heater rated at 1000 W is
1.
2.
3.
4.
The power of a source of energy-producing 600 J energy in 30 s is
1.1800 W
2. 200 W
3. 100 W
4. 20 W
What is the current (l) in the circuit?
1.
2.
3.
4.
What is immaterial for an electric fuse wire?
1. Its specific resistance
2. its radius
3. its length
4. current flowing through it
Two wires of same metal have the same length but their cross-sectional area in the ratio 3:1. They are joined in series. The resistance of the thicker wire is . The total resistance of the combination will be
1.
2.
3.
4.