In a common emitter amplifier, the phase difference between input signal and output signal is:

1. zero             

2. $\mathrm{\pi }$               

3. $\frac{\mathrm{\pi }}{2}$               

4. $\frac{\mathrm{\pi }}{4}$

In an NPN transistor amplifier, if 98% of electrons emitted from the emitter reach the collector, then the value of collector current for the base current of 40 $\mu$A will be:

1. 1.96 mA             

2. 1.92 mA             

3. 1.96 A             

4. 1.92 A

The energy band diagrams for semiconductor samples of silicon are as shown. We can assert that:

If the reverse bias in a junction diode is changed from \(5~\text V\) to \(15~\text V\) then the value of current changes from \(38~\mu \text{A}\) to \(88~\mu \text{A}.\) The resistance of the junction diode will be:
1. \(4\times10^{5}\) 
2. \(3\times10^{5}\)
3. \(2\times10^{5}\)
4. \(10^{6}\)

In a common emitter circuit, if V_CC is changed by 0.2 V, collector current changes by 4 x 10^–3 mA. The output resistance will be:

1. 10 k$\mathrm{\Omega }$ 

2. 30 k$\mathrm{\Omega }$ 

3. 50 k$\mathrm{\Omega }$ 

4. 70 k$\mathrm{\Omega }$

An LED is constructed from a \(\mathrm{p\text{-}n}\) junction diode using \(\mathrm{GaAsP}.\) The energy gap is \(1.9~\text{eV}.\) The wavelength of the light emitted will be equal to:
1. \(10.4 \times 10^{-26}~ \text{m}\)
2. \(654~ \text{nm}\)
3. \(654~ \text{m}\)
4. \(654\times 10^{-11}~\text{m}\)

In a given circuit as shown the two input waveforms \(A\) and \(B\) are applied simultaneously. The resultant waveform \(Y\) is:
     

1.		2.
3.		4.

In the circuit given below, if \(V(t)\) is the sinusoidal voltage source, then the voltage drop \(V_{AB}(t)\) across the resistance \(R\):

A \(2\) V battery is connected across the points \(A\) and \(B\) as shown in the figure given below. Assuming that the resistance of each diode is zero in forward bias and infinity in reverse bias, the current supplied by the battery when its positive terminal is connected to \(A\) is: