Question

Energy of an isolated system is constant. It can neither be created nor be destroyed but it
can be transformed from one type to another. For example, when an object falls on the
ground from a certain height, its kinetic energy is converted into other forms of energy such
as sound energy, heat energy, light energy, etc. When petroleum oil is burnt, chemical
energy is converted into other form of energy specially light and heat energy. In process of
generation of hydroelectricity, water in reservoir is flown to rotate the turbine to generate
electricity. In this process, potential energy (water in reservoir) is converted to kinetic
energy flowing water) to electrical energy. When speaker which doesn't have battery is
turned on, electrical energy is converted to sound energy.
Answer the question 1 to 4 on the basis of above paragraph
1. Which law states "Energy of an isolated system is constant. It can neither be created nor
be destroyed but it can be transformed from one type to another."
2. In which of the following chemical energy is converted into light and heat energy.
a. loud speaker b. petroleum oil c. hydropower station d. electric fan
3. In process of generation of hydroelectricity, water stored in reservoir has
a. kinetic energy
b. electrical energy
C. chemical energy
d. sound energy
4. In electric heater
_energy is converted into
energy
5. The kinetic energy of an object moving with a velocity of 5 m/s is 25 J. Find the mass of
the object. What will be its kinetic energy when its velocity is 2 times? Justify your answer.
6. Define power. What is the commercial unit of energy. One commercial unit of energy
equals to how many joules. A family uses 250 units of electrical energy during a moth.
Calculate the electrical energy in joules.​

Answer 1

Answer:

The laws of reflections are:

1) The incident ray, the normal and the reflected ray, all lie in the same plane.

2) The angle of incidence is equal to the angle of reflection.

Explanation: