#### Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Click to Chat

1800-5470-145

+91 7353221155

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 high resistance voltmeter is connected to a dry cell battery. The voltmeter reads 10 volts. When a 20 ohm resistor is connected across the terminals of the battery the voltmeter reading becomes 8 volts. What is the internal resistance of the battery?

419 Points
10 years ago

Dear Vidisha

If voltmeter resistance is high then it practically no current through it.

in first case it shows the emf, E of the cell

E=10 volts

in second case I=E/R+r  , R=20 and r is internal resistance

E-Ir=8

E-Er/(R+r) = 8

put value of E=10 and R=20

10 - 10r/20+r = 8

solving we get r=5 ohm

All the best.

AKASH GOYAL

Please feel free to post as many doubts on our discussion forum as you can. We are all IITians and here to help you in your IIT JEE preparation.

Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.