Question

An electric heater of resistance 8 ohm draws 15A form the service mains 2 hours calculate the rate at which heat is developed in the heater

Answer 1

Answer:

Given R = 8 ohm

I =15 a t = 2 hours

Ww know that

V =iR

V=120 volt

Now p=vi

P=120 *15

=1800

Now heat is 120*2

240 joule

Answer 2

$\Huge{\underline{\underline{\blue{\mathfrak{Answer :}}}}}$

$\large{\underline{\underline{\red{\sf{Given :}}}}}$

Resistane (R) = 8 Ω

Electric current (I) = 15 A

Time (T) = 2 h = 2 * 60 * 60 = 7200 s

$\rule{200}{2}$

$\large{\underline{\underline{\pink{\sf{To \: Find :}}}}}$

We have to find Power

$\rule{200}{2}$

$\large{\underline{\underline{\orange{\sf{Solution :}}}}}$

We know that,

$\Huge{\boxed{\gray{\sf{H = I^2 R T}}}}$

(Put Values)

H = (15)² * 8 * 7200

H = 225 * 57,600

H = 12,960,000

$\large{\boxed{\pink{\sf{H \: = \: 12,960,000 \: J}}}}$

$\rule{200}{2}$

$\Huge{\boxed{\purple{\sf{Power = \frac{Heat}{Time}}}}}$

Power = 12960000/7200

Power = 1800

$\large{\boxed{\pink{\sf{Power \: = \: 1800 \: Js^{-1}}}}}$

$\rule{200}{2}$

Important Formula's :-

1. V = W/Q
2. V = IR
3. I = Q/T
4. P =VI
5. P = I²R
6. P = V²/R
7. H = I² RT
8. P = H/T
9. P = I²R
10. H = VIT
11. W = VQ