Question

The heater at 220 volt hits of particular volume of water in 5 minutes the same heater at 110 volt will heat the same volume to same temperature in how many minutes

Answer 1

AS HEAT DISSIPATED BY A RESISTANCE = VIt= I^2Rt
potential becomes half
so current also becomes half (V=IR) heater(resistance)is constant
to equalise the heat time should be 4 times of 1st activity
i;e-5*4=20 minutes.

Answer 2

We know , H=V²t/R

Given , V₁ = 220 v.

V₂ = 110 v .

t₁ = 5 m.

t₂ = 10 n.

H₁ = H₂.

The amount of heat required to heat the same amount of water will be same.

The resistance will also be same.

V₁² × t₁ / R₁ = V₂² t² / R²

= > R₁ = R₂.

= > V₁² × t₁  = V₂² t₂

So,

220² × 5 = 110² × t

= > 4840 × 5 = 1210 × t

= > t = 4840/1210 × 5

= > 4 × 5

= > 20 minutes.

Time will be 20 minutes .