Question

How much time heater will take to increase the temperature of 100g water by 50°C, if resistance of heating
coil is 484 ohm and supply voltage is 220 V.ac
A) 210 S
B) 42 S
C) 200 S
D) 50 S​

Answer 1

Answer:

A)210 S

Explanation:

given,

M = 100g =100×10^-3kg

∆t = 50℃

R = 484

V = 220

I^2Rt =MS∆t

V^2/R^2 ×R ×t = MS∆t [I = V/R]

V^2/Rt = MS∆t

t = MS∆t/V^2 R

WKT, S = 4.2×10^3

t = 100× 4.2×10^3×50 / (220)^2 × 484

t = 210 S