CBSE Class 12 Physics Question Paper 2021 Set E

CBSE Class 12 Physics Question Paper 2021 Set E. Students can download the last year board exams question papers using the link below. Free download of examination question papers with solutions. Last 10 year question papers should be practised to get better marks in examinations.

1. If the radius of the Gaussian surface enclosing a point charge is halved, how does the electric flux through the Gaussian surface change?

2. Draw the graph of resistivity against absolute temperature T for an alloy used for making standard resistance wires.

3. What is the condition in terms of angle of diffraction for observing first minimum in case of diffraction due to a single slit?

4. An air core coil 'L' and a bulb 'B ' are connected in series in the ac mains as shown in the figure. The bulb glows with some brightness. How will the glow of the bulb change if the frequency of the ac source is changed? Give reason in support of your answer.

5. A given logic gate gives high state of output only when both of its inputs are at high state. Identify this gate and give its logic symbol.

6. An electric dipole with electric dipole moment 4x10-9Cm oriented at 30o with the direction of a uniform electric field of magnitude 5x 10⁴N/C. Calculate the magnitude of the torque acting on the dipole.

7. Identify the following electromagnetic radiation as per wavelength given below. Write one application of each. a) 1mm b) 10^-12m c) 10^-8m

8. Distinguish between point to point communication and broadcasting mode. Give one example of each.

9. The ratio between the de-Broglie wavelengths associated with protons accelerated though a potential of 512V and alpha particles accelerated through a potential of 'x' is found to be same.

Find the value of x.

10. A metal has threshold wavelength of 600nm. Calculate (i) Threshold frequency

(ii) Work function of metal in eV.

11. Explain why high frequency carrier waves are used for effective transmission of signals. A message signal of 12 kHz and peak voltage 20V is used for modulating a carrier wave frequency 12MHz and peak voltage 30V. Calculate the (i) modulation index (ii) side band frequencies.

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