Question

400J of heat is produced in 4s in a 4ohm resistor.Find the pottential difference across the resistor

Answer 1

Answer:

25v

Explanation:

H=I^2Rt................... (1)

where H=heat

I=current

R=resistance

t=time

v=voltage

equetion 1 can also written as H=vRt

so

400=v16

so v=400/16

hence v=25volt

Answer 2

Answer:

20 V

Explanation:

Given :

Heat H = 400 J

Resistance R = 4 Ω

Time t = 4 sec

We are asked to find potential difference V :

We know :

H = I² R t

= > I² = H / R t

Putting values here we get :

= > I² = 400 / 4 × 4

= > I = √ 25 A

= > I = 5 A

From Ohm's law we know :

V = I R

Putting I = 5 A and R = 4 Ω

= > V = 5 × 4 V

= > V = 20 V

Therefore we get required potential difference.