Electrons are accelerated through and incident on a crystal with interatomic spacing
. Calculate the de Broglie wavelength and the first-order Bragg diffraction angle.
In a photoelectric effect experiment, it is seen that when light of wavelength is incident on a metal, the measured photoelectric current drops to zero at a potential
. Calculate the work function of the metal and its cut-off frequency for photoelectric effect.
An electric field of is applied along the direction of motion of an electron moving with a speed of 0.6c. Calculate the acceleration of the electron.
A particle moves with speed 0.8c. Calculate its momentum, kinetic energy and total energy.
See Answer →A star emits light of wavelength and recedes from Earth at speed 0.50c. Calculate the observed wavelength.
A spaceship approachin Earth at a speed c/2, shoots a canister at a speed of 0.80c. Calculate the velocity of the canister for an observer on Earth if (i) the canister if it is shot directly toward Earth and (ii) if it is shot directly away from Earth.
See Answer →A rod has a proper length of . An observer measures its length as
. Calculate the speed of the rod.
Design an astable multivibrator using IC 555 to generate the square wave of 20 kHz frequency.
See Answer →Refer to Fig. 15.4 in your study material showing the geometry of the electron beam deflection in a CRT. In this CRT the length of deflection plates (L) is and the distance between screen and centre of the deflection plates (R) is
. Accelerating voltage applied to the anode is 1200 V and applied deflection voltage is 80 V. If the deflection suffered by the electron beam at the edge of the deflection plate (h) is 1 mm, calculate the plate separation (s). Determine the deflection observed on the CRT screen (y) and calculate the deflection sensitivity.
Design and draw a circuit using an op-amp to get at output for input less than
and
at output for input greater than
.
You want to amplify a triangular wave signal of amplitude and
frequency. Which characteristic of op-amp will be significant in this case? What is its minimum value?
Design and draw shunt voltage regulator using a zener diode to provide output with maximum load current of
. Assume that the input unregulated dc voltage is
and the minimum zener current is
.
The turns ratio of a transformer used in half wave rectifier is 30:1. The primary is connected to the power mains: . If the diode resistance in forward bias is
and the load resistance, RL is
, determine
i) the peak value, the dc value and the rms value of current;
ii) the ripple factor
raw the circuit of a Colpitts oscillator. Calculate its frequency of oscillation if value of both the capacitors is and inductor is
.
Why LC oscillators are preferred over RC oscillators to generate high frequencies? Why 2-stage amplifier is required in Wien bridge oscillator in contrast to a single stage amplifier in the phase shift oscillator?
See Answer →What are the advantages of resistance-capacitance (RC) coupling between the two stages of a cascade amplifier?
See Answer →How class B amplifier is more efficient than class A amplifier? What will be the effect on the output of a push-pull amplifier if unmatched transistors are used?
See Answer →In the universal biasing of a transistor, which resistor acts as a feedback element? How does it provide stability to the circuit?
See Answer →Draw the circuit of 2's complement binary adder-subtractor and using it explain the addition of binary equivalent of decimal number 9 and binary equivalent of decimal number 4 .
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