Answer:

Explanation:
Power is defined as the energy produced (E) per unit of time (t):

This means that the energy produced in the Sun each second (1 s), given the power
, is

Each p-p chain reaction produces an amount of energy of

in order to get the total number of p-p chain reactions per second, we need to divide the total energy produced per second by the energy produced by each reaction:

Answer:
The pressure on the floor is 12 Pascal(Pa).
Explanation:
Given,
Force (F) = 240N
Area (A) = 20 cm^2
Pressure (P) = ?
we know that,
P = F/A
= 240/ 20
= 12 Pa
Answer:Reflection
Explanation:
The throwing back of a sound wave without absorbing it is called reflection
In acoustic reflection of sound is termed as echo i.e. sound arrived at the listener after a particular delay depending upon the position of barrier to the observer.
The reflection of sound is used in many devices like megaphone, trumpets, etc. It is also used in auditorium such that the ceiling of the auditorium is curved for multiple reflections of sound so that sound can be reached at every corner of the auditorium.
Answer:
Sample Response: In a vacuum, there are no atoms or particles that interfere with the path of light. However, in other media, the speed of light is lower than 3.0 × 108 m/s because the wave is continuously absorbed and re-emitted by each atom in its path. The differences in speed are due to the composition of the medium and the density of the particles in the medium.
Explanation: