Question

A current of 2 ampere passing through a conductor produces 80 joule of heat in 10 seconds.the resistance of the conductor in ohm is​

Answer 1

The general formula for calculating Resistance is R = V/I but according to the details and values provided in the question, it will be calculated through the formula of heat.

As we all know that,

H = I²RT

where

H = Heat in joules (J).

I   = Current in amperes (A).

R  = Resistance in ohm (Ω).

T  = Time in seconds (s).

ATQ,

H = 80 J

I   = 2 A

T  = 10 s

R  = ?

Substitute the given values in the equation,

80 = (2)² x R x 10

80 = 4 x R x 10

80 = 40 x R

80/40 = R

2 = R

 or

R = 2  Ω

∴ Option (B) 2 is the correct option.

Answer 2

Current ( I) = 2 Ampere

It produces 80 J of heat in 10 seconds

So Power = 80/10 = 8 watts

Now We know Power = i^2 R ( R is resistance)

because We know Energy = q ( ∆V)

As work done to bring a charge a from one point to another is potential energy

As work done to bring unit charge from infinity to point is potential at that point

So U = q ( ∆V) as defined

As i = dq/dt

So Energy = i dt ( ∆v)

power = i (∆v)

As v= i R

Power = i^2 R

So

Power = 2^2 R

As power is 8 W

So

8 = 4 R

R = 8/4 = 2 ohm

So ❤❤( B) is coreect❤❤

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