Refraction is the change in direction of a wave, caused by the change in the wave's speed. Examples of waves include sound waves and light waves. Refraction is seen most often when a wave passes from one transparent medium to another transparent medium. Different types of medium include air and water. When a wave passes from one transparent medium to another transparent medium, the wave will change its speed and its direction. For example, when a light wave travels through air and then passes into water, the wave will slow and change direction.
Answer:
6 days.
Explanation:
From radioactivity, The expression for half life is given as,
R/R' = 2⁽ᵃ/ᵇ)................... Equation 1
Where R = original mass of the radioactive substance, R' = Remaining mass of the radioactive substance after decay, a = Total time taken to decay, b = half life.
Given: R = 80 g, R' = 10 g, b = 2 days.
Substitute into equation 1
80/10 = 2⁽ᵃ/²⁾
8 = 2⁽ᵃ/²⁾
2³ = 2⁽ᵃ/²)
Equating the base and solving for a
3 = a/2
a = 2×3
a = 6 days.
Answer:
F = 2.49 x 10⁻⁹ N
Explanation:
The electrostatic force between two charged bodies is given by Colomb's Law:

where,
F = Electrostatic Force = ?
k = colomb's constant = 9 x 10⁹ N.m²/C²
q₁ = charge on proton = 1.6 x 10⁻¹⁹ C
q₂ = second charge = 1.4 C
r = distace between charges = 0.9 m
Therefore,

<u>F = 2.49 x 10⁻⁹ N</u>
Answer:v=3.28 m/s
Explanation:
Given
mass of rock 
diameter of circle 
radius 
At highest Point

At highest Point N=0 because mass is just balanced by centripetal Force
thus 




Answer:
C)T
Explanation:
The period of a mass-spring system is:

As can be seen, the period of this simple harmonic motion, does not depend at all on the gravitational acceleration (g), neither the mass nor the spring constant depends on this value.