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
When we throw a ball into the air, it falls back. The force responsible for this is
muscular force
gravitational force
mechanical force
None of these
Work is said to be done when __________ produces displacement of a body.
force
energy
distance
speed
Electrical energy can be produced by
coal
water
uranium
all of the above
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
The ultimate source of our energy is
sun
wind
plants
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 above transformation takes place in
electric bulb
electric heater
battery cell
solar cell
Radha pushed a wall but failed to move it then
energy is not spent but work is done
energy is spent but work is not done
energy is not spent and work is not done
energy is spent and work is done
Machines cannot do the following
machines make work easy
machine increase the speed of doing work
machines change the direction of force
machines produce energy
