Question

Help me Physics Newton.
It's really Urgents.

Keeping the potential difference constant, the resistance of an electric circuit is doubled.
State the change in the reading of an ammeter connected in the circuit.​

Answer 1

GIVEN

Potential difference is constant

Resistance is doubled

TO FIND :- Change in current

SOLUTION

For solving this problem we should have use Ohm's law

It states that the potential difference across two ends of a conductor is directly proportional to the amount of current flowing through it.

It gives a constant Resistance (R)

V = I x R

Hence , V is directly propertional to I and R

But R = V/I

so I is inversely propertional to R

Now, we can attend the given question,

Let R' be new resistance

R' = 2R (R is old Resistance)

and V is constant in both cases

Hence,

Old current I = V/R ...eq.01

New Current I' = V /R'

I' = V/2R

=> I' = V/R × 1/2

=> I' = I × 1/2

=> I' = I/2

Hence current is halfed

Because new current = old current/2

(ANS)