Science (English Medium) Class 12 - CBSE Important Questions for Physics

Answer the following question :

Distinguish between digital and analogue signals.

Plot a graph showing variation of current versus voltage for the material GaAs ?

Identify the gate equivalent to the circuit shown in the figure. Write its truth table.

Identify the equivalent gate represented by the circuit shown in the figure. Draw its logic symbol and write the truth table.

In the circuit shown in the figure, identify the equivalent gate of the circuit and make its truth table.

Figure shows a block diagram of a transmitter identify the boxes ‘X’ and ‘Y’ and write their functions.

Figure shows a block diagram of a detector for amplitude modulated signal. Identify the boxes ‘X’ and ‘Y’ and write their functions.

What happens to the width of depletion player of a p-n junction when it is (i) forward biased, (ii) reverse biased?

You are given a circuit below. Write its truth table. Hence, identify the logic operation carried out by this circuit. Draw the logic symbol of the gate it corresponds to.

Draw the circuit diagram of an illuminated photodiode in reverse bias. How is photodiode used to measure light intensity?

Explain the formation of depletion layer and potential barrier in a p−n junction.

In the figure given below the input waveform is converted into the output waveform by a device ‘X’. Name the device and draw its circuit diagram.

Identify the logic gate represented by the circuit as shown and write its truth table.

With the help of circuit diagram explain the working principle of a transistor amplifier as an oscillator.

Distinguish between a conductor, a semiconductor and an insulator on the basis of energy band diagrams.

The following figure shows the input waveforms (A, B) and the output waveform (Y) of a gate. Identify the gate, write its truth table and draw its logic symbol.

Draw a circuit diagram to study the input and output characteristics of an n-p-n transistor in its common emitter configuration. Draw the typical input and output characteristics.

Explain, with the help of a circuit diagram, the working of n-p-n transistor as a common emitter amplifier.

How is a zener diode fabricated so as to make it a special purpose diode? Draw I-V characteristics of zener diode and explain the significance of breakdown voltage.

Explain briefly, with the help of a circuit diagram, how a p-n junction diode works as a half wave rectifier.

What will be the values of input A and B for the Boolean expression `overline ((A +B) .(A*B)) =1?`