2.3.6 Quiz: Energy and Sustainability Question 8 of 10
A lamp has a power of 120 W and is left on for 24 hours. A television has a
power of 350 W and is left on for 3 hours. Which statement correctly
compares the energy used by these devices?
A. The television uses 6,588,000 J less than the lamp.
B. The television uses 3,780,000 J less than the lamp.
C. The television uses 10,368,000 J more than the lamp.
D. The television uses 2,356,000 J more than the lamp.

The correct option is (A).

Explanation:

Given that,

Power of a lamp, P = 120 W

Time, t = 24 hours = 86400 s

The power of a television, P' = 350 W

Time, t' = 3 hours = 10800 s

The power of a device is given by :

P = E/t, E is energy

For lamp,

E = Pt

E = 120 × 86400 = 10,368,000 J

For Television,

E' = P't'

E = 350 × 10800= 37,800,00J

Difference in energies,

E-E' = 10,368,000 - 37,800,00

= 6,588,000

Hence, the television uses 6,588,000 J less than the lamp.

cant without the picture! ?