1. Find the resistivity of a material (in Ohms-cm) of wire whose resistance is 5 ohms. (Assume length of the wire is 15 m, diameter of wire is 0.15 cm) ?

5.87*10^-5

5.87*10^-7

7.87*10^-5

7.87*10^-7

Answer: 5.87*10^-5

Explanation:


2. Find the resistivity of a material (in Ohms-cm) of wire whose resistance is 5 ohms. (Assume length of the wire is 15 m, diameter of wire is 0.15 cm) ?

5.87*10^-5

5.87*10^-7

7.87*10^-5

7.87*10^-7

Answer: 5.87*10^-5

Explanation:


3. The two metal plates having an area of 50 sq. m are separated by a dielectric material having thickness of 4 mm and relative permittivity of 9. Calculate the capacitance (in micro-Farad) across the metal plates ?

0.5

0.996

1.76

2.1

Answer: 0.996

Explanation:


4. A choke of 20 H carries a current of 600 mA. Calculate the energy stored (in J) in form of magnetic field by the choke ?

0.5

1.2

2.5

3.6

Answer: 3.6

Explanation:


5. Three electric lamps of 70 W each are connected in parallel across AC mains. What is the total power consumed (in W) by the parallel combination ?

70

140

210

380

Answer: 210

Explanation:


6. The dimensions of a cuboidal metal strip are a= 5 cm, b= 15 cm and c =10 cm What is the ratio of resistances Ra : Rb : Rc between the respective pairs of opposite faces ?

1:3:5

1:3:2

1:9:4

1:9:16

Answer: 1:9:4

Explanation:


7. What is the efficiency (in %) of the circuit, when the maximum power is delivered to the load ?

40

50

70

80

Answer: 50

Explanation:


8. In which combination, the electrical appliances are connected at home ?

Series

Parallel

Series-parallel

None of these

Answer: Parallel

Explanation:


9. The open circuit voltage across the load terminals is 30 V. The terminal voltage drops to 20 V, when the load of 15 ohms is connected across the open circuited terminals. What is the internal resistance (in ohms) of the source ?

5.5

6

7

7.5

Answer: 7.5

Explanation:


10. QID : 318 - At the maximum power transfer condition, the power transferred to the load is 70 W. What is the total power (in W) generated by the voltage source ?

135

138

140

144

Answer: 140

Explanation: