Subject

Physics

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
Advertisement

 Multiple Choice QuestionsShort Answer Type

Advertisement

21.

Draw the output waveform at X, using the given inputs A and B for the logic circuit shown below. Also, identify the logic operation performed by this circuit.   


From the waveform given, we can say that 

which is the Boolean expression of OR.

The output waveform for OR gate is given by, 


1920 Views

Advertisement
22.

Name the semiconductor device that can be used to regulate an unregulated dc power supply. With the help of I-V characteristics of this device, explain its working principle.

1014 Views

23.

Draw the transfer characteristic curve of a base biased transistor in CE configuration. Explain clearly how the active region of the V0 versus Vi curve in a transistor is used as an amplifier. 

1169 Views

24.

(i) Define modulation index.

(ii) Why is the amplitude of modulating signal kept less than the amplitude of carrier wave?
2403 Views

Advertisement
25.

An electron and a photon each have a wavelength 1.00 nm. Find

(i) their momenta,

(ii) the energy of the photon and

(iii) the kinetic energy of electron.
2347 Views

26.

Draw a schematic diagram showing the (i) ground wave (ii) sky wave and (iii) space wave propagation modes for EM waves.

Write the frequency range for each of the following:

(i) Standard AM broadcast

(ii) Television

(iii) Satellite communication
2225 Views

27.

Describe Young's double slit experiment to produce interference pattern due to a monochromatic source of light. Deduce the expression for the fringe width.

1381 Views

28.

Use Huygens principle to verify the laws of refraction.

3996 Views

Advertisement
29.

(a) Describe briefly, with the help of suitable diagram, how the transverse nature of light can be demonstrated by the phenomenon of polarization.

(b) When unpolarized light passes from air to a transparent medium, under what condition does the reflected light get polarized? 
1284 Views

30.

The energy levels of a hypothetical atom are shown below. Which of the shown transitions will result in the emission of a photon of wavelength 275 nm?

Which of these transitions correspond to emission of radiation of (i) maximum and (ii) minimum wavelength? 


1361 Views

Advertisement