multiple choice questions in electrical

1. Which among these are the main characteristics of a fuse element?
a. Low melting point                 b. High conductivity

c. Least deterioration due to oxidation d. All of the above

Q2. Which among the following statement is true related to fuse?
a. Greater the current smaller is the time taken by the fuse to blow out.
b. Greater the current greater is the time taken by the fuse to blow out.
c. The current is directly proportion to the blow out time of fuse.
d. Is dependent on the temperature and atmospheric conditions.

Q3. Which among these is the least expensive protection for over current in low voltage system?
a. Rewirable fuse.       b. Isolator.       c. Circuit breaker.       d. Air breaker switch

6. What is fusing factor?
a. The ratio of current rating of the fuse to the minimum fusing current.
b. The ratio of minimum fusing current to the current rating of the fuse.
c. The ratio of maximum fusing current to the current rating of the fuse.
d. The ratio of minimum fusing current to the voltage rating of the fuse

Q7. What should be the value of fusing factor?
a. Equal to zero           b. Equal to one            c. Less than one         d. More than one

Q2. If the strands of the fusing wire are twisted, what happens to the fusing current?
a. Increases    b. Reduces.   

c. No change/ remains same     d. Depends on the value of current, increases or decreases.      

Q3. What is the cut off current in the fuse?
a. Maximum value actually reached.              b. Rms value actually reached.
c. Average value actually reached.                             d. None of the above

83)   Which part of the circuit breaker is helpful in breaking the current?

a. Trip coil.      b. Contacts.   c. Medium       d. Handle.

Q3. ELCB is an/a

a. magnetic switch      b. electromagnetic switch   c. electronic switch     d. mechanical switch