Question

6000J of heat is generated when 2A current is passed through a resistor for 4 minutes . what is the resistance of the resistor?
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Answer 1

Answer:

6.25 Ohms

Explanation:

W = 6000 J

I = 2 A

t = 4 mins = 4 × 60 = 240 s

W = VIt

6000 = V × 2 × 240

V = 6000 ÷ 480 = 12.5

Now, W = V²t/R

6000 = (12.5 × 12.5 ×240)/R

∴ R = (12.5 × 12.5 × 240) / 6000

⇒R = 6.25 Ohms

Hope it helps...

Answer 2

Given :

Heat generated = 6000 J

Current passed = 2 A

Time = 4 minutes = 4 × 60 = 240 sec

To Find :

The resistance of the resistor

Solution :

The heat generated by the current 'i', through the conductor having resistance 'R' for the time 'T' is given as -

Heat generated (H) = i²RT

As Heat (H) = 6000J; Current (i) = 2 A; Time (T) = 240 sec

⇒           6000           = (2)²× R × 240

⇒           6000           = 4 × R × 240

⇒              R               =  $\frac{6000}{960}$

∴               R               =  6.25 ohm

Therefore, the resistance of the resistor is 6.25 ohm.