CBSE Class 12 Physics 2024 question paper (55/4)

1. A.
   $\dfrac{q^2}{8\pi\varepsilon_0 a}$
2. B.
   $-\dfrac{6q^2}{8\pi\varepsilon_0 a}$
3. C.
   $\dfrac{-7q^2}{8\pi\varepsilon_0 a}$
4. D.
   $\dfrac{9q^2}{8\pi\varepsilon_0 a}$

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1. A.
   $-2$ pC
2. B.
   $-3$ pC
3. C.
   $-5$ pC
4. D.
   $-15$ pC

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1. A.
   there is a minimum frequency of incident radiation below which no electrons are emitted.
2. B.
   the maximum kinetic energy of photoelectrons depends only on the frequency of incident radiation.
3. C.
   when the metal surface is illuminated, electrons are ejected from the surface after sometime.
4. D.
   the photoelectric current is independent of the intensity of incident radiation.

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1. A.
   $r_n \propto n$
2. B.
   $r_n \propto \dfrac{1}{n}$
3. C.
   $r_n \propto n^2$
4. D.
   $r_n \propto \dfrac{1}{n^2}$

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1. A.
   East
2. B.
   West
3. C.
   North
4. D.
   South

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1. A.
   small and negative
2. B.
   small and positive
3. C.
   large and negative
4. D.
   large and positive

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1. A.
   0.1 mA
2. B.
   1 mA
3. C.
   10 mA
4. D.
   0.1 A

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1. A.
   R
2. B.
   $\sqrt{R}$
3. C.
   $R^{\frac{3}{2}}$
4. D.
   $R^2$

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1. A.
   $\sqrt{3}$
2. B.
   $\dfrac{1}{\sqrt{3}}$
3. C.
   3
4. D.
   $\dfrac{1}{3}$

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1. A.
   zero
2. B.
   $\pi$
3. C.
   $\dfrac{\pi}{2}$
4. D.
   $\dfrac{\pi}{4}$

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1. A.
   $t = \dfrac{nT}{8}$
2. B.
   $t = \dfrac{nT}{4}$
3. C.
   $t = \dfrac{nT}{2}$
4. D.
   $t = nT$

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1. A.
   equally spaced and equally intense.
2. B.
   further apart and stronger in intensity.
3. C.
   closer together and stronger in intensity.
4. D.
   closer together and weaker in intensity.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   0.001 eV
2. B.
   0.01 eV
3. C.
   0.72 eV
4. D.
   1.1 eV

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1. A.
   $2 \times 10^{24}\ \mathrm{m^{-3}}$
2. B.
   $4 \times 10^{23}\ \mathrm{m^{-3}}$
3. C.
   $1 \times 10^{22}\ \mathrm{m^{-3}}$
4. D.
   $5 \times 10^{22}\ \mathrm{m^{-3}}$

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1. A.
   electrons diffuse from p-region into n-region and holes diffuse from n-region into p-region.
2. B.
   both electrons and holes diffuse from n-region into p-region.
3. C.
   electrons diffuse from n-region into p-region and holes diffuse from p-region into n-region.
4. D.
   both electrons and holes diffuse from p-region into n-region.

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1. A.
   diffusion current is large and drift current is small.
2. B.
   diffusion current is small and drift current is large.
3. C.
   both the diffusion and the drift currents are large.
4. D.
   both the diffusion and the drift currents are small.

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1. A.
   25 Hz, 50 Hz
2. B.
   25 Hz, 100 Hz
3. C.
   50 Hz, 50 Hz
4. D.
   50 Hz, 100 Hz

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1. A.
   $\dfrac{-5}{6}\mathrm{D}$
2. B.
   $\dfrac{-5}{3}\mathrm{D}$
3. C.
   $\dfrac{4}{3}\mathrm{D}$
4. D.
   $\dfrac{3}{2}\mathrm{D}$

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1. A.
   $\dfrac{5}{3}$
2. B.
   $\dfrac{4}{3}$
3. C.
   $\dfrac{3}{2}$
4. D.
   $\dfrac{7}{5}$

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1. A.
   increases when the lens is dipped in water.
2. B.
   increases when the wavelength of incident light decreases.
3. C.
   increases with decrease in radius of curvature of its surface.
4. D.
   decreases when the lens is cut into two identical parts along its principal axis.

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1. A.
   10 cm, left of lens
2. B.
   10 cm, right of lens
3. C.
   20 cm, left of lens
4. D.
   20 cm, right of lens

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1. A.
   real, 24 cm
2. B.
   virtual, 12 cm
3. C.
   real, 32 cm
4. D.
   virtual, 18 cm

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1. A.
   $\dfrac{11}{48}\dfrac{q}{\pi\varepsilon_0 L}$
2. B.
   $\dfrac{8q}{36\pi\varepsilon_0 L}$
3. C.
   $\dfrac{5q}{24\pi\varepsilon_0 L}$
4. D.
   $\dfrac{1}{16}\dfrac{q}{\pi\varepsilon_0 L}$

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1. A.
   $q_1 > q_2 > q_3$
2. B.
   $q_1 > q_3 > q_2$
3. C.
   $q_3 > q_2 > q_1$
4. D.
   $q_3 > q_1 > q_2$

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1. A.
   small and negative
2. B.
   small and positive
3. C.
   large and negative
4. D.
   large and positive

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1. A.
   R
2. B.
   $\sqrt{R}$
3. C.
   $R^{\frac{3}{2}}$
4. D.
   $R^2$

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1. A.
   straight line path
2. B.
   circular path
3. C.
   helical path
4. D.
   parabolic path

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1. A.
   there is a minimum frequency of incident radiation below which no electrons are emitted.
2. B.
   the maximum kinetic energy of photoelectrons depends only on the frequency of incident radiation.
3. C.
   when the metal surface is illuminated, electrons are ejected from the surface after sometime.
4. D.
   the photoelectric current is independent of the intensity of incident radiation.

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1. A.
   zero
2. B.
   $\pi$
3. C.
   $\dfrac{\pi}{2}$
4. D.
   $\dfrac{\pi}{4}$

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1. A.
   $r_n \propto n$
2. B.
   $r_n \propto \dfrac{1}{n}$
3. C.
   $r_n \propto n^2$
4. D.
   $r_n \propto \dfrac{1}{n^2}$

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1. A.
   10 mA
2. B.
   20 mA
3. C.
   40 mA
4. D.
   80 mA

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1. A.
   0.1 mA
2. B.
   1 mA
3. C.
   10 mA
4. D.
   0.1 A

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1. A.
   equally spaced and equally intense.
2. B.
   further apart and stronger in intensity.
3. C.
   closer together and stronger in intensity.
4. D.
   closer together and weaker in intensity.

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1. A.
   $t = \dfrac{nT}{8}$
2. B.
   $t = \dfrac{nT}{4}$
3. C.
   $t = \dfrac{nT}{2}$
4. D.
   $t = nT$

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   $\dfrac{-5}{6}\mathrm{D}$
2. B.
   $\dfrac{-5}{3}\mathrm{D}$
3. C.
   $\dfrac{4}{3}\mathrm{D}$
4. D.
   $\dfrac{3}{2}\mathrm{D}$

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1. A.
   $\dfrac{5}{3}$
2. B.
   $\dfrac{4}{3}$
3. C.
   $\dfrac{3}{2}$
4. D.
   $\dfrac{7}{5}$

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1. A.
   increases when the lens is dipped in water.
2. B.
   increases when the wavelength of incident light decreases.
3. C.
   increases with decrease in radius of curvature of its surface.
4. D.
   decreases when the lens is cut into two identical parts along its principal axis.

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1. A.
   10 cm, left of lens
2. B.
   10 cm, right of lens
3. C.
   20 cm, left of lens
4. D.
   20 cm, right of lens

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1. A.
   real, 24 cm
2. B.
   virtual, 12 cm
3. C.
   real, 32 cm
4. D.
   virtual, 18 cm

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1. A.
   0.001 eV
2. B.
   0.01 eV
3. C.
   0.72 eV
4. D.
   1.1 eV

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1. A.
   $2 \times 10^{24}\ \mathrm{m^{-3}}$
2. B.
   $4 \times 10^{23}\ \mathrm{m^{-3}}$
3. C.
   $1 \times 10^{22}\ \mathrm{m^{-3}}$
4. D.
   $5 \times 10^{22}\ \mathrm{m^{-3}}$

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1. A.
   electrons diffuse from p-region into n-region and holes diffuse from n-region into p-region.
2. B.
   both electrons and holes diffuse from n-region into p-region.
3. C.
   electrons diffuse from n-region into p-region and holes diffuse from p-region into n-region.
4. D.
   both electrons and holes diffuse from p-region into n-region.

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1. A.
   diffusion current is large and drift current is small.
2. B.
   diffusion current is small and drift current is large.
3. C.
   both the diffusion and the drift currents are large.
4. D.
   both the diffusion and the drift currents are small.

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1. A.
   25 Hz, 50 Hz
2. B.
   25 Hz, 100 Hz
3. C.
   50 Hz, 50 Hz
4. D.
   50 Hz, 100 Hz

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1. A.
   $2pE$
2. B.
   $-2pE$
3. C.
   $pE$
4. D.
   zero

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1. A.
   attractive and $\dfrac{q\lambda}{2\pi\varepsilon_0 x}$
2. B.
   repulsive and $\dfrac{q\lambda}{2\pi\varepsilon_0 x}$
3. C.
   attractive and $\dfrac{q\lambda}{\pi\varepsilon_0 x}$
4. D.
   repulsive and $\dfrac{q\lambda}{\pi\varepsilon_0 x}$

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1. A.
   zero
2. B.
   $\pi$
3. C.
   $\dfrac{\pi}{2}$
4. D.
   $\dfrac{\pi}{4}$

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1. A.
   equally spaced and equally intense.
2. B.
   further apart and stronger in intensity.
3. C.
   closer together and stronger in intensity.
4. D.
   closer together and weaker in intensity.

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1. A.
   $\dfrac{3\mu_0 I\,I_1}{2\pi r}$, towards A
2. B.
   $\dfrac{3\mu_0 I\,I_1}{2\pi r}$, towards B
3. C.
   $\dfrac{3\mu_0 I\,I_1}{4\pi r}$, towards A
4. D.
   $\dfrac{3\mu_0 I\,I_1}{4\pi r}$, towards B

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1. A.
   $t = \dfrac{nT}{8}$
2. B.
   $t = \dfrac{nT}{4}$
3. C.
   $t = \dfrac{nT}{2}$
4. D.
   $t = nT$

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1. A.
   R
2. B.
   $\sqrt{R}$
3. C.
   $R^{\frac{3}{2}}$
4. D.
   $R^2$

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1. A.
   0.1 mA
2. B.
   1 mA
3. C.
   10 mA
4. D.
   0.1 A

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1. A.
   $\dfrac{1}{\sqrt{2}}(i_1 + i_2)$
2. B.
   $\dfrac{1}{\sqrt{2}}(i_1 - i_2)$
3. C.
   $\dfrac{1}{\sqrt{2}}\sqrt{(i_1^2 + i_2^2)}$
4. D.
   $\dfrac{1}{\sqrt{2}}(i_1^2 + i_2^2)$

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1. A.
   there is a minimum frequency of incident radiation below which no electrons are emitted.
2. B.
   the maximum kinetic energy of photoelectrons depends only on the frequency of incident radiation.
3. C.
   when the metal surface is illuminated, electrons are ejected from the surface after sometime.
4. D.
   the photoelectric current is independent of the intensity of incident radiation.

Tap an option to check your answer.

1. A.
   small and negative
2. B.
   small and positive
3. C.
   large and negative
4. D.
   large and positive

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1. A.
   $r_n \propto n$
2. B.
   $r_n \propto \dfrac{1}{n}$
3. C.
   $r_n \propto n^2$
4. D.
   $r_n \propto \dfrac{1}{n^2}$

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
3. C.
   If Assertion (A) is true and Reason (R) is false.
4. D.
   If both Assertion (A) and Reason (R) are false.

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1. A.
   0.001 eV
2. B.
   0.01 eV
3. C.
   0.72 eV
4. D.
   1.1 eV

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1. A.
   $2 \times 10^{24}\ \mathrm{m^{-3}}$
2. B.
   $4 \times 10^{23}\ \mathrm{m^{-3}}$
3. C.
   $1 \times 10^{22}\ \mathrm{m^{-3}}$
4. D.
   $5 \times 10^{22}\ \mathrm{m^{-3}}$

Tap an option to check your answer.

1. A.
   electrons diffuse from p-region into n-region and holes diffuse from n-region into p-region.
2. B.
   both electrons and holes diffuse from n-region into p-region.
3. C.
   electrons diffuse from n-region into p-region and holes diffuse from p-region into n-region.
4. D.
   both electrons and holes diffuse from p-region into n-region.

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1. A.
   diffusion current is large and drift current is small.
2. B.
   diffusion current is small and drift current is large.
3. C.
   both the diffusion and the drift currents are large.
4. D.
   both the diffusion and the drift currents are small.

Tap an option to check your answer.

1. A.
   25 Hz, 50 Hz
2. B.
   25 Hz, 100 Hz
3. C.
   50 Hz, 50 Hz
4. D.
   50 Hz, 100 Hz

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1. A.
   $\dfrac{-5}{6}\mathrm{D}$
2. B.
   $\dfrac{-5}{3}\mathrm{D}$
3. C.
   $\dfrac{4}{3}\mathrm{D}$
4. D.
   $\dfrac{3}{2}\mathrm{D}$

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1. A.
   $\dfrac{5}{3}$
2. B.
   $\dfrac{4}{3}$
3. C.
   $\dfrac{3}{2}$
4. D.
   $\dfrac{7}{5}$

Tap an option to check your answer.

1. A.
   increases when the lens is dipped in water.
2. B.
   increases when the wavelength of incident light decreases.
3. C.
   increases with decrease in radius of curvature of its surface.
4. D.
   decreases when the lens is cut into two identical parts along its principal axis.

Tap an option to check your answer.

1. A.
   10 cm, left of lens
2. B.
   10 cm, right of lens
3. C.
   20 cm, left of lens
4. D.
   20 cm, right of lens