Answer:
C ) 1.53
Explanation:
The critical angle of a material is given by the formula

where
c is the critical angle
n is the refractive index
This formula is valid if the second medium is air (which is the case of the problem).
In this problem, we know the critical angle:

Therefore we can rearrange the equation to find the refractive index:

Answer:
17.3 m
Explanation:
Given that,
Mass of a hammer is 0.58 kg
Velocity with which the hammer slides is 6.69 m/s at constant speed.
The roof makes an angle of 18 ◦ with the horizontal, and its lowest point is 18.2 m from the ground. We need to find the horizontal distance traveled by the hammer between the time is leaves the roof of the house and the time it hits the ground. Firstly, we will find the time taken by the hammer when it reaches ground in vertical direction.

Putting all the values,

Neglecting negative value,
To find horizontal distance, multiply 2.72 s with the horizontal component of velocity.

1. True
2. True
3. True
4. True
5. False
6. False
7. True
A needle valve and collar.
Yes because if they are further away it makes it hard for them to attract each other