Question

How many differenct 7-digit numbers can be written using only three digits 4 , 5 and 8 such that the digit 8 occurs twice in each number?

Answer 1

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A varying current in a coil changes from 10 A to zero in 0.5 sec. If the average e.m.f induced in the coil is 220V, the self-inductance of the coil is

(a)    5 H  

(b)    6 H  

        (c)    11 H

(d)    12 H

5 years ago

Answers : (1)

(c)
Initial current (I1) = 10 A; Final current
(I2) = 0; Time (t) = 0.5 sec and induced e.m.f.
        (e) = 220 V.
Induced e.m.f. (E)