PHYSICS
1. If \(c\) is the velocity of light in free space, the correct statements about photons among the following are:
| (A) |
The energy of a photon is \(E=h\nu.\) |
| (B) |
The velocity of a photon is \(c.\) |
| (C) |
The momentum of a photon, \(p={\dfrac{h\nu}{c}}.\) |
| (D) |
In a photon-electron collision, both total energy and total momentum are conserved. |
| (E) |
Photon possesses a positive electric charge. |
Choose the correct answer from the options given below:
| 1. |
(A), (B), (C) and (D) only |
| 2. |
(A), (C) and (D) only |
| 3. |
(A), (B), (D) and (E) only |
| 4. |
(A) and (B) only |
2. The
\(I\text-V\) characteristics shown below are exhibited by a:
| 1. |
Light-emitting diode |
2. |
Zener diode |
| 3. |
Photodiode |
4. |
Solar cell |
3. The graph that shows the variation of
\({\dfrac{1}{\lambda^2}}\) with the kinetic energy
\(E\) (where
\(\lambda\) is the de-Broglie wavelength of a free particle) is:
4. Select the correct statements among the following:
| A. |
slow neutrons can cause fission in \(\mathrm U_{92}^{235}\) than fast neutrons. |
| B. |
\(\text{α-rays}\) are helium nuclei. |
| C. |
\(\text{β-rays}\) are fast-moving electrons or positrons. |
| D. |
\(\gamma\text-\text{rays}\) are electromagnetic radiations of wavelengths larger than \(X\text-\)rays. |
Choose the most appropriate answer from the options given below:
| 1. |
A, B, and C only |
2. |
A, B, and D only |
| 3. |
A and B only |
4. |
C and D only |
5. The radius of innermost orbit of a hydrogen atom is
\(5.3 \times 10^{-11}~\text m.\) What is the radius of the third allowed orbit of a hydrogen atom?
| 1. |
\(4.77~ \mathring{A}\) |
2. |
\(0.53~ \mathring{A}\) |
| 3. |
\(1.06~ \mathring{A}\) |
4. |
\(1.59~ \mathring{A}\) |
6. A nucleus with mass number \(240\) breaks into fragments each of mass number \(120.\) The binding energy per nucleon of unfragmented nuclei is \(7.6~\text{MeV}\) while that of fragments is \(8.5~\text{MeV}.\) The total gain in the binding energy in the process is:
| 1. |
\(804~\text{MeV}\) |
2. |
\(216~\text{MeV}\) |
| 3. |
\(0.9~\text{MeV}\) |
4. |
\(9.4~\text{MeV}\) |
7. The work functions of Caesium
\((\mathrm{Cs}),\) Potassium
\((\mathrm{K}),\) and Sodium
\((\mathrm{Na})\) are
\(2.14~\text{eV},\) \(2.30~\text{eV}\) and
\(2.75~\text{eV}\) respectively. If incident electromagnetic radiation has an incident energy of
\(2.20~\text{eV},\) which of these photosensitive surfaces may emit photoelectrons?
| 1. |
\(\mathrm{Na}\) only |
2. |
\(\mathrm{Cs}\) only |
| 3. |
both \(\mathrm{Na}\) and \(\mathrm{K}\) |
4. |
\(\mathrm{K}\) only |
8. The energy equivalent of
\(0.5~\text g\) of a substance is:
| 1. |
\(4.5\times10^{13}~\text J\) |
2. |
\(1.5\times10^{13}~\text J\) |
| 3. |
\(0.5\times10^{13}~\text J\) |
4. |
\(4.5\times10^{16}~\text J\) |
9. Some energy levels of a molecule are shown in the figure with their wavelengths of transitions.
Then:
1.
\(\lambda_{3}>\lambda_{2},\lambda_{1}=2\lambda_{2}\)
2.
\(\lambda_{3}>\lambda_{2},\lambda_{1}=4\lambda_{2}\)
3.
\(\lambda_{1}>\lambda_{2},\lambda_{2}=2\lambda_{3}\)
4.
\(\lambda_{2}>\lambda_{1},\lambda_{2}=2\lambda_{3}\)
10. Two radiations of photons energies \(1\) eV and \(2.5\) eV, successively illuminate a photosensitive metallic surface of work function \(0.5\) eV. The ratio of the maximum speeds of the emitted electrons is:
1. \(1:2\)
2. \(1:1\)
3. \(1:5\)
4. \(1:4\)
11. The radius of the first permitted Bohr orbit for the electron in a hydrogen atom is 0.5 Å, and its ground state energy is \(-13.6~\text{eV}.\) If the electron in the hydrogen atom is replaced by a muon \((\mu^{-}),\) which has the same charge as the electron but is \(207\) times more massive, what will be the new values for the first Bohr radius and ground state energy?
| 1. |
\(0.53\times10^{-13}~\text{m}, ~-3.6~\text{eV}\) |
| 2. |
\(25.6\times10^{-13}~\text{m}, ~-2.8~\text{eV}\) |
| 3. |
\(2.56\times10^{-13}~\text{m}, ~-2.8~\text{keV}\) |
| 4. |
\(2.56\times10^{-13}~\text{m}, ~-13.6~\text{eV}\) |
12. If in a \(\mathrm{p\text{-}n}\) junction, a square input signal of \(10~\text{V}\) is applied as shown,
then the output across \(R_L\) will be:
13. A nucleus of mass number \(189\) splits into two nuclei having mass numbers \(125\) and \(64.\) The ratio of the radius of two daughter nuclei respectively is:
1. \(25:16\)
2. \(1:1\)
3. \(4:5\)
4. \(5:4\)
14. Radiation of energy \(E\) falls normally on a perfectly reflecting surface. The momentum transferred to the surface is:
(\(c\) = velocity of light)
| 1. |
\(E \over c\) |
2. |
\(2E \over c\) |
| 3. |
\(2E \over c^2\) |
4. |
\(E \over c^2\) |
15. Let
\(L_1\) and
\(L_2\) be the orbital angular momentum of an electron in the first and second excited states of the hydrogen atom, respectively. According to Bohr's model, the ratio
\(L_1:L_2\) is:
| 1. |
\(1:2\) |
2. |
\(2:1\) |
| 3. |
\(3:2\) |
4. |
\(2:3\) |
16. The circuit represents a full wave bridge rectifier when switch \(S\) is open. The output voltage \((V_0)\) pattern across \(R_L\) when \(S\) is closed:
17. An electron of mass \(m\) with an initial velocity \(\overrightarrow v= v_0\hat i\)\( ( v_o > 0 ) \) enters in an electric field \(\overrightarrow E = -E_0 \hat i\) \((E_0 = \text{constant}>0)\) at \(t=0.\) If \(\lambda_0,\) is its de-Broglie wavelength initially, then what will be its de-Broglie wavelength at time \(t?\)
| 1. |
\(\frac{\lambda_0}{\left(1+ \frac{eE_0}{mv_0}t\right)}\) |
2. |
\(\lambda_0\left(1+ \frac{eE_0}{mv_0}t\right)\) |
| 3. |
\(\lambda_0 t\) |
4. |
\(\lambda_0\) |
18. Match
List-I (Spectral Series) with
List-II (corresponding wave number expressions).
|
List-I
(Series) |
|
List-II
(Wave number in \(\text{cm}^{–1}\)) |
| A. |
Balmer series |
I. |
\( R\left(\dfrac{1}{1^2}-\dfrac{1}{n^2}\right) \) |
| B. |
Lyman series |
II. |
\( R\left(\dfrac{1}{4^2}-\dfrac{1}{n^2}\right) \) |
| C. |
Brackett series |
III. |
\( R\left(\dfrac{1}{5^2}-\dfrac{1}{n^2}\right) \) |
| D. |
Pfund series |
IV. |
\( R\left(\dfrac{1}{2^2}-\dfrac{1}{n^2}\right)\) |
Choose the correct answer from the options given below:
| 1. |
A-I, B-IV, C-III, D-II |
| 2. |
A-II, B-III, C-IV, D-I |
| 3. |
A-IV, B-I, C-II, D-III |
| 4. |
A-III, B-II, C-I, D-IV |
19. The incorrect statement about the property of a Zener diode is:
| 1. |
Zener voltage remains constant at the breakdown. |
| 2. |
It is designed to operate under reverse bias. |
| 3. |
The depletion region formed is very wide. |
| 4. |
\(\mathrm{p}\) and \(\mathrm{n}\) regions of the Zener diode are heavily doped. |
20. If
\(\phi\) is the work function of photosensitive material in electron-volts and light of a wavelength of numerical value
\(\lambda=\dfrac{{hc}}{{e}}\) metres is incident on it with energy above its threshold value at an instant, then the maximum kinetic energy of the photo-electron ejected by it at that instant is (in SI units):
(take
\(h\) as Plank's constant and
\(c\) as the velocity of light in free space)
| 1. |
\({e}+2\phi \) |
2. |
\(2{e}-\phi \) |
| 3. |
\({e}-\phi \) |
4. |
\({e}+\phi \) |
21. An electron in hydrogen atom makes a transition
\(n_1 \rightarrow n_2\) where
\(n_1\) and
\(n_2\) are principal quantum numbers of the two states. Assuming Bohr's model to be valid, the time period of the electron in the initial state is eight times that in the final state. The possible values of
\(n_1\) and
\(n_2\) are:
| 1. |
\( n_1 = 6~\text{and}~n_2 = 2\) |
2. |
\( n_1 = 8~\text{and}~ n_2 = 1\) |
| 3. |
\( n_1 = 8~\text{and}~ n_2 = 2\) |
4. |
\(n_1 = 4~\text{and}~n_2 = 2\) |
22. Which one of the following represents the forward bias diode?
23. A particle of mass
\(m\) is moving around the origin with a constant force
\(F\) pulling it towards the origin. If Bohr model is used to describe its motion, the radius
\(r\) of the
\(n^{\text{th}}\) orbit and the particle's speed
\(v\) in the orbit depend on
\(n\) as:
| 1. |
\(r \propto n^{2/3}; v \propto n^{1/3}\) |
2. |
\(r \propto n^{4/3}; v \propto n^{-1/3}\) |
| 3. |
\(r \propto n^{1/3}; v \propto n^{1/3}\) |
4. |
\(r \propto n^{1/3}; v \propto n^{2/3}\) |
24. An LED is constructed from a \(\mathrm{p\text{-}n}\) junction diode using \(\mathrm{GaAsP}.\) The energy gap is \(1.9~\text{eV}.\) The wavelength of the light emitted will be equal to:
1. \(10.4 \times 10^{-26}~ \text{m}\)
2. \(654~ \text{nm}\)
3. \(654~ \text{m}\)
4. \(654\times 10^{-11}~\text{m}\)
25. When an
\(\alpha\text-\)particle of mass
\(m\) moving with velocity
\(v\) bombards on a heavy nucleus of charge
\(Ze\), its distance of closest approach from the nucleus depends on
\(m\) as:
| 1. |
\(\dfrac{1}{\sqrt{m}}\) |
2. |
\(\dfrac{1}{m^{2}}\) |
| 3. |
\(m\) |
4. |
\(\dfrac{1}{m}\) |
26. \(\mathrm{C}\) and
\(\mathrm{Si}\) both have the same lattice structure, having
\(4\) bonding electrons in each. However,
\(\mathrm{C}\) is an insulator whereas
\(\mathrm{Si}\) is an intrinsic semiconductor. This is because:
| 1. |
in the case of \(\mathrm{C},\) the valence band is not completely filled at absolute zero temperature. |
| 2. |
in the case of \(\mathrm{C},\) the conduction band is partly filled even at absolute zero temperature. |
| 3. |
the four bonding electrons in the case of \(\mathrm{C}\) lie in the second orbit, whereas in the case of \(\mathrm{Si},\) they lie in the third. |
| 4. |
the four bonding electrons in the case of \(\mathrm{C}\) lie in the third orbit, whereas for \(\mathrm{Si},\) they lie in the fourth orbit. |
27. The Binding energy per nucleon of \(^{7}_{3}\mathrm{Li}\) and \(^{4}_{2}\mathrm{He}\) nucleon are \(5.60~\text{MeV}\) and \(7.06~\text{MeV}\), respectively. In the nuclear reaction \(^{7}_{3}\mathrm{Li} + ^{1}_{1}\mathrm{H} \rightarrow ^{4}_{2}\mathrm{He} + ^{4}_{2}\mathrm{He} +Q\), the value of energy \(Q\) released is:
| 1. |
\(19.6~\text{MeV}\) |
2. |
\(-2.4~\text{MeV}\) |
| 3. |
\(8.4~\text{MeV}\) |
4. |
\(17.3~\text{MeV}\) |
28. A \(\mathrm{p} \text-\)type extrinsic semiconductor is obtained when Germanium is doped with:
1. antimony
2. phosphorous
3. arsenic
4. boron
29. Which of the following options represents the variation of photoelectric current with the property of light shown on the
\(x \text{-}\)axis?
| 1. |
(A) and (D) |
2. |
(B) and (D) |
| 3. |
(A) only |
4. |
(A) and (C) |
30. The ratio of nuclear densities and nuclear volumes of
\(^{56}_{26}Fe\) and
\(^{4}_{2}He\) are, respectively:
| 1. |
\(13:1\) and \(14:1\) |
2. |
\(14:1\) and \(1:1\) |
| 3. |
\(1:1\) and \(14:1\) |
4. |
\(1:1\) and \(13:1\) |
31. A radioactive nucleus
\(_{\mathrm{Z}}^{\mathrm{A}}\mathrm{X}\) undergoes spontaneous decay in the sequence
\(_{\mathrm{Z}}^{\mathrm{A}}\mathrm{X}\rightarrow \mathrm{B}_{\mathrm{Z-1}}\rightarrow \mathrm{C}_{\mathrm{Z-3}}\rightarrow \mathrm{D}_{\mathrm{Z-2}}\) where
\(\mathrm{Z}\) is the atomic number of element
\(\mathrm{X}.\) The possible decay particles in the sequence are:
| 1. |
\(\beta^{+}, ~\alpha, ~\beta^{-}\) |
2. |
\(\beta^{-}, ~\alpha, ~\beta^{+}\) |
| 3. |
\(\alpha, ~\beta^{-},~\beta^{+}\) |
4. |
\(\alpha, ~\beta^{+},~\beta^{-}\) |
32. The wavelength of the Lyman series of hydrogen atom appears in:
| 1. |
visible region |
| 2. |
far infrared region |
| 3. |
ultraviolet region |
| 4. |
infrared region |
33. The number of photons per second on an average emitted by a source of monochromatic light of wavelength \(600~\text{nm}\), when it delivers the power of \(3.3\times 10^{-3}\) watt will be:\((h = 6.6\times10^{-34}~\text{J-s})\)
1. \(10^{16}\)
2. \(10^{15}\)
3. \(10^{18}\)
4. \(10^{17}\)
34. What happens to the mass number and the atomic number of an element when it emits \(\gamma\text{-}\)radiation?
| 1. |
mass number decreases by four and atomic number decreases by two. |
| 2. |
mass number and atomic number remain unchanged. |
| 3. |
mass number remains unchanged while the atomic number decreases by one. |
| 4. |
mass number increases by four and the atomic number increases by two. |
35. When the light of frequency \(2\nu_0\) (where \(\nu_0\) is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is \(v_1.\) When the frequency of the incident radiation is increased to \(5\nu_0,\) the maximum velocity of electrons emitted from the same plate is \(v_2.\) What will be the ratio of \(v_1\) to \(v_2?\)
| 1. |
\(1:2\) |
2. |
\(1:4\) |
| 3. |
\(4:1\) |
4. |
\(2:1\) |
36. The given circuit has two ideal diodes connected as shown in the figure below. The current flowing through the resistance \(R_1\) will be:
| 1. |
\(2.5~\text{A}\) |
2. |
\(10.0~\text{A}\) |
| 3. |
\(1.43~\text{A}\) |
4. |
\(3.13~\text{A}\) |
37. Given below are two statements:
| Statement I: |
Atoms are electrically neutral as they contain equal number of positive and negative charges. |
| Statement II: |
Atoms of each element are stable and emit their characteristic spectrum. |
In the light of the above statements, choose the most appropriate answer from the options given below:
| 1. |
Both Statement I and Statement II are incorrect. |
| 2. |
Statement I is correct but Statement II is incorrect. |
| 3. |
Statement I is incorrect but Statement II is correct. |
| 4. |
Both Statement I and Statement II are correct. |
38. When a uranium isotope
\(_{92}^{235}\mathrm{U}\) is bombarded with a neutron, it generates
\(_{36}^{89}\mathrm{Kr}\), three neutrons and:
| 1. |
\(_{40}^{91}\mathrm{Zr}\) |
2. |
\(_{36}^{101}\mathrm{Kr}\) |
| 3. |
\(_{36}^{103}\mathrm{Kr}\) |
4. |
\(_{56}^{144}\mathrm{Ba}\) |
39. Which input
\((A,B)-\) output
\((Y)\) combination correctly represents the given logic circuit?
| 1. |
\(A=1,B=1,Y=1\) |
| 2. |
\(A=0,B=1,Y=1\) |
| 3. |
\(A=1,B=0,Y=0\) |
| 4. |
\(A=0,B=0,Y=1\) |
40. How does the binding energy per nucleon vary with the increase in the number of nucleons?
| 1. |
decrease continuously with mass number. |
| 2. |
first decreases and then increases with an increase in mass number. |
| 3. |
first increases and then decreases with an increase in mass number. |
| 4. |
increases continuously with mass number. |
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