it's either the first or second choice
Answer:
The value of acceleration due to gravity is greater in terai than in mountain. In terai region the radius of earth is less as it lies close to the centre of the earth. Thus, the value of g is more in terai region.
The light must be either very dim or else non-existent.
We can't see the light wave or the label.
Answer:
The number of turns, N = 1750
Explanation:
It is given that,
The inner radius of a toroid, r = 12 cm
Outer radius, r' = 15 cm
The magnetic field at points within the coils 14 cm from its center is, 
R = 14 cm = 0.14 m
Current, I = 1.5 A
The formula for the magnetic field at some distance from its center is given by :



N = 1750
So, the number of turns must have in a toroidal solenoid is 1750. Hence, this is the required solution.