ECET EEE 2012-9

1. The effective resistance between terminals A and B in the below figure is

A. r
B. 2r
C. 3r
D. 4r

Answer : A. r
Explanation:-

2. If I be the current, C be the capacitance and V be the potential differences, the I/CV wil have the unit of

A. Time
B. Power
C. Frequency
D. Reactive power

Answer : C. Frequency
Explanation:-

3. In a series R-C circuit excited by a DC voltage E. the initial current is

A. E/R
B. 0
C. E/C
D. C/E

Answer : B. 0
Explanation:-

4. The strength of electromagnet can be increased by

A. decreasing the length of the conductor
B. increaing the length of the conductor
C. Increasing the number of turns
D. decreasing the number of turns

Answer : B. increaing the length of the conductor
Explanation:-

5. Tesla is a unit of

A. Flux
B. Field strength
C. current
D. Flux density

Answer : D. Flux density
Explanation:-

6. According to joules law heat produced by an electric current is proportional to

A. square of the resistance
B. square of the current
C. potential difference
D. square of the time

Answer : B. square of the current
Explanation:-

7. The thevenins equivalent resistance Rth for given below network is

A. 1 ohm
B. 2 ohms
C. 4 ohms
D. infinity

Answer : B. 2 ohms
Explanation:-

8. In a differential compound generator, the series field turns are provided on

A. Armature
B. commutator
C. Interpole
D. Main pole

Answer : D. Main pole
Explanation:-

9. The function of the commutator in a dc machine is

A. to change alternating current to direct current
B. to improve commutation
C. for easy speed control
D. to change alternating voltage to direct voltage

Answer : A. to change alternating current to direct current
Explanation:-

10. If N is the speed and P is number of poles, then the frequency of induced emf in DC generator will be

A. NP/60
B. NP/120
C. NP/2
D. NP

Answer : B. NP/120
Explanation:-