EASY
9th CBSE
IMPORTANT
Earn 100

Mention the commercial unit of energy. Express it in terms of joules. Calculate the energy in joule consumed by a device of 60 W in 1 hour.

Important Questions on Work and Energy

EASY
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 11 - Work and Energy>ASSESS YOURSELF>Q 35
State and define SI unit of power.
MEDIUM
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 11 - Work and Energy>ASSESS YOURSELF>Q 35
A person carrying 10 bricks each of mass 2.5 kg on his head moves to a height 20 m in 50 s. Calculate power spent in carrying bricks by the person. (g=10 m s-2)
MEDIUM
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 11 - Work and Energy>ASSESS YOURSELF>Q 36
Two bulbs of 40 W each are lighted for eight hours daily. Find the cost of electrical energy consumed by them in one week at ₹3 per unit.
MEDIUM
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 11 - Work and Energy>ASSESS YOURSELF>Q 37
A man whose mass is 50 kg moves up 15 steps each of height 15 cm in 45 seconds of time. Calculate the power used in climbing those stairs. (g=10 m s-2)
EASY
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 11 - Work and Energy>ASSESS YOURSELF>Q 38
A battery lights a bulb. Describe the energy change involved in the process.
MEDIUM
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 11 - Work and Energy>ASSESS YOURSELF>Q 38
Calculate the amount of work needed to stop a car of 500 kg, moving at a speed of 36 km h-1.