In the given figure, a diode D is connected to an external resistance R = 100 Ω  and an e.m.f of 3.5 V. If the barrier potential developed across the diode is 0.5 V, the current in the circuit will be


1. 30mA

2. 40mA

3. 20mA

4. 35mA

The input signal given to a CE amplifier having a voltage gain of 150 is V_i=2cos(15t+π/3). The corresponding output signal will be

(a)300cos(15t+π/3)

(b)75cos(15t+2π/3)

(c)2cos(15t+5π/3)

(d)300cos(15t+4π/3)

The given graph represents the V-I characteristic for a semiconductor device. Which of the following statement is correct?

The barrier potential of a p-n junction depends on

(i)type of semiconductor material

(ii)amount of doping

(iii)temperature

Which one of the following is correct

1. (i) and (ii)only

2. (ii) only

3. (ii) and (iii)only

4. (i),(ii) and (iii)

In a n-type semiconductor, which of the following statement is true ?

(a) Electrons are majority carriers and trivalent atoms are dopants

(b) Electrons are minority carriers and pentavalent atoms are dopants

(c) Holes are minority carriers and pentavalent atoms are dopants

(d) Holes are majority carriers and trivalent atoms are dopants

In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance 0.03 mho and current gain 25. If the above transistor is replaced with another one with transconductance 0.02 mho and current gain 20, the voltage gain will 

(a)$\frac{2}{3}G$                                       (b)$1.5G$

(c)$\frac{1}{3}G$                                        (d)$\frac{5}{4}G$

The output (x) of logic circuit shown in figure will be 

(1) $X=\stackrel{=}{A}·\stackrel{=}{B}$

(2) $X=\overline{A.B}$

(3)$X=A·B$

(4)$X=\overline{A+B}$

Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is

(1)0.75A                             

(2)zero

(3)0.25A                               

(4)0.5A    

C and Si both have same lattice structure,having 4 bonding electrons in each.However, C is insulator whereas Si is intrinsic semiconductor. This is because 

1. in case of C, the valence band is not completely filled at absolute zero temperature

2. in case of C,the condition band is partly filled even at absolute zero temperature 

3. the four bonding electrons in the case of C lie in the second orbit,Whereas in the case of Si they lie in the third

4 .the four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit

Transfer characteristic [output voltage $\left(V_{\mathrm{o}}\right)$ vs input voltage $\left(V_i\right)$] for a base biased transistor in CE configuration is as shown in the figure. For using transistor as a switch, it is used:
                     

1. in region III

2. both in region (I) and (III)

3. in region II

4. in region I