Click to Chat

1800-2000-838

+91-120-4616500

CART 0

• 0

MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping
```         A coil of wire is would on an iron core looped back on itself so that the core has two sets of closely wound identicalcoaxial coils in series carrying currents in opposite direction, the self inductance of such a system is(a) zero (b) very large (c) very small (d) difficult to determine

q2)  A coil of wire forming an inductor of inductance L is shetched to double its length, the inductance of the coil will(a) change to L/4 (b) not change at all (c) change to L/2 (d) change to L/8

Q3)  A ac − circuit has L = 12.6 mH and C = 1.15 μF, the amount of resistance that should be inserted into the circuit inseries to reduce the resonant frequency by 0.01 is(a) 2.96 W (b) 8.76 W (c) 29.6 W (d) 87.6 W```
7 years ago

vishal ....
16 Points
```										hi,
for 1st question answer is c.....this method is ususlly used in resistance boxes to reduce inductance
2)the inductance a coil of N turns and lenth l and of area of cross section A is given by
L=mrmoN2A/l
as the coil is streched its area of cross section changes but volume remains same.
so, to calculate the new inductance eliminating A is necessary as it is unknown that by which amount area is decrease
L=mrmoN2A/l                     mr=relative permeability,mo=absolute permeability
L=kAl/l2                          k=mrmoN2=constant
L=kv/l2                           v=volume
when lenght is doubled
L'=kv/(2l)2
L'=kv/4l2
L'=L/4

```
7 years ago
Think You Can Provide A Better Answer ?

## Other Related Questions on Electromagnetic Induction

View all Questions »
• Complete JEE Main/Advanced Course and Test Series
• OFFERED PRICE: Rs. 15,900
• View Details
Get extra Rs. 900 off
USE CODE: Susan900
• Electricity and Magnetism
• OFFERED PRICE: Rs. 1,696
• View Details
Get extra Rs. 900 off
USE CODE: Susan900