Study of the energy transformations shown here. In which of the following cases is this taking place?
Glowing of an electric torch
Photosynthesis in plants
Generation of electricity in windmills
Burning of woods
Electrical energy can be produced by
coal
water
uranium
all of the above
An electrical heater converts
heat energy to electrical energy
electrical energy to heat energy
light energy to electrical energy
electrical energy to muscular energy
The force which pulls a body towards the earth is called
friction
gravity
tension
collision
Which one of the following statements is NOT true?
Friction makes a moving object slow down and stop
Friction between two surfaces will make them hot
Friction also enables an object to stay in a stationary position
Friction decreases if roughness of an object increases
The ultimate source of our energy is
sun
wind
plants
In which one of the following activities is force used for pulling?
Blowing air into a balloon
Cycling
Stretching a rubber band
None of these
Work is said to be done when __________ produces displacement of a body.
force
energy
distance
speed
When we throw a ball into the air, it falls back. The force responsible for this is
muscular force
gravitational force
mechanical force
When a bomb explodes, it converts
heat energy to light and sound energy
chemical energy to heat, light and electrical energy
chemical energy to heat, light and sound energy
heat energy to electrical, sound and light energy
