Answer : The process of changing a property of a wave to transmit information is called Modulation.
Explanation :
Modulation is the process of changing the property of wave to transmit information. This is done with the help of modulator.
In modulation, the message signal is superimposed on a high frequency signal. A sine wave ( usually high frequency ) is used as a high frequency carrier wave.
Modulation can be done in many ways like :
(1) Frequency modulation
(2) Amplitude modulation
(3) Pulse modulation
A perfect elastic collision is defined as one in which there is no loss of kinetic energy in the collision. An inelastic collision is one in which part of the kinetic energy is changed into another form of energy in the collision. Well hope this answers your question :)
The heat released by the water when it cools down by a temperature difference

is

where
m=432 g is the mass of the water

is the specific heat capacity of water

is the decrease of temperature of the water
Plugging the numbers into the equation, we find

and this is the amount of heat released by the water.
Answer:
d. 37 °C
Explanation:
= mass of lump of metal = 250 g
= specific heat of lump of metal = 0.25 cal/g°C
= Initial temperature of lump of metal = 70 °C
= mass of water = 75 g
= specific heat of water = 1 cal/g°C
= Initial temperature of water = 20 °C
= mass of calorimeter = 500 g
= specific heat of calorimeter = 0.10 cal/g°C
= Initial temperature of calorimeter = 20 °C
= Final equilibrium temperature
Using conservation of heat
Heat lost by lump of metal = heat gained by water + heat gained by calorimeter

Answer:

Explanation:
This problem is approached using Coulomb's law of electrostatic attraction which states that the force F of attraction or repulsion between two point charges,
and
is directly proportional to the product of the charges and inversely proportional to the square of their distance of separation R.

where k is the electrostatic constant.
We can make k the subject of formula as follows;

Since k is a constant, equation (2) implies that the ratio of the product of the of the force and the distance between two charges to the product of charges is a constant. Hence if we alter the charges or their distance of separation and take the same ratio as stated in equation(2) we will get the same result, which is k.
According to the problem, one of the two identical charges was altered from
to
and their distance of separation from
to
, this also made the force between them to change from
to
. Therefore as stated by equation (2), we can write the following;

Therefore;

From equation (4) we now make the new force
the subject of formula as follows;

then cancels out from both side of the equation, hence we obtain the following;

From equation (4) we can now write the following;

This could also be expressed as follows;
