$\mathrm{In} \mathrm{the} \mathrm{given} \mathrm{circuit} \mathrm{power}$
$\mathrm{developed} \mathrm{in} 1\mathrm{k\Omega } \mathrm{resistor} \mathrm{is}$

1.  36 mW

2.  12 mW

3.  144 mW

4.  64 mW

The given circuit has two ideal diodes connected as shown in the figure below. The current flowing through the resistance $R_1$ will be

(1) 2.5 A                     

(2) 10.0 A

(3) 1.43 A                   

(4) 3. 13 A

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

A Zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit, as shown in the figure. The current through the diode is:

1. 10 mA

2. 15 mA

3. 20 mA

4. 5 mA

A p-n photodiode is fabricated from a semiconductor with a band gap of $2.5 \mathrm{eV}.$ It can detect a signal of wavelength 

(1) $6000 \stackrel{\circ }{\mathrm{A}}$                                   
(2) $4000 \mathrm{nm}$
(3) $6000 \mathrm{nm}$                                 
(4) $4000 \stackrel{\circ }{\mathrm{A}}$

A p-n photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly

1. $10\times {10}^{14} Hz$                              2. $5\times {10}^{14} Hz$

3. $1\times {10}^{14} Hz$                                4. $20\times {10}^{14} Hz$

PN-junction diode works as a insulator, if connected

(1) To A.C.                             

(2) In forward bias

(3) In reverse bias                   

(4) None of these

The PN junction diode is used as

(1) An amplifier                       

(2) A rectifier

(3) An oscillator                       

(4) A modulator

Zener breakdown in a semi-conductor diode occurs when

(1) Forward current exceeds certain value

(2) Reverse bias exceeds certain value

(3) Forward bias exceeds certain value

(4) Potential barrier is reduced to zero

When the P end of P-N junction is connected to the negative terminal of the battery and the N end to the positive terminal of the battery, then the P-N junction behaves like 

(1) A conductor                       

(2) An insulator

(3) A super-conductor             

(4) A semi-conductor