Question

A torch bulb is rated at 3V and 600mA. Calculate it’s (a) Power b) Resistance c) Energy consumed if it is lighted for 4 Hrs.
Please help any mod

Answer 1

Answer:

7.2 W

Explanation:

Given : The potential of tourch bulb V = 3V Current I = 600 ma

=600*10-¹=0.6A

To find: a) Power P = ? b) Resistance, R = ?c) Energy consumed = ? a) P = VI =

3*0.6=1.8W

V=IR

=R=V/I

b) Resistance, R =

3/0.6= 5

c) Energy consumed for 4hr = power of the bulb

time =1.8*4

Energy, E = 7.2 W

Answer 2

Answer :-

(a) Power of the bulb is 1.8 W .

(b) It's resistance is 5 Ω .

(c) Energy consumed is 25920 J .

Explanation :-

We have :-

→ Potential difference (V) = 3 V

→ Current flowing (I) = 600 mA

→ Time taken (t) = 4 hrs

= 4(3600)

= 14400 sec

______________________________

Firstly, let's convert the unit of current from mA to A.

⇒ 1 mA = 0.001 A

⇒ 600 mA = 600(0.001)

⇒ 0.6 A

For power :-

P = VI

⇒ P = 3 × 0.6

⇒ P = 1.8 W

For resistance :-

By Ohm's Law :-

V = IR

⇒ 3 = 0.6 × R

⇒ R = 3/0.6

⇒ R = 5 Ω

For energy consumed :-

E = Pt

⇒ E = 1.8 × 14400

⇒ E = 25920 J