Question

400 joule of heat is produced in 4 seconds in a 4 ohm resistor find the potential difference across the resistor

Answer 1

V=IR

V=W/Q

W/Q=IR

W/Q=Q/T×R (I=Q/T)

400/Q=Q/4×4

400=Q×Q

20C=Q

V=W/Q

V=400/20

V=20V

Answer 2

Answer:

The potential difference across the resistor is 20 volts.

Explanation:

We are given:

Heat produced= 400J

Time= 4 sec

Resistance= 4 ohm

We need to calculate the potential difference which is the voltage difference in the electric potential across two points.

Now we know: Heat = Power×Time

Or Q=P×T

Q=I×V×T(Power= Current (I)×Voltage(V))  

Q=(V/R)×V×T (Current= $\frac{V o l t a g e}{r e s t s t a n c e})$

400=(V/4)×V×4  

$400=V^{2}$

V=20V  

We have already said that the “potential difference” across the resistor is equal to the voltage. So the Potential Difference = 20V