The least value varies depends on ammeter range. In the given question, ammeter range is not mentioned. So, the least value of an ammeter is 0.1 or 0.5 (depends on ammeter range).
<u>Explanation:</u>
The least value of an ammeter is the measure of the smallest number which can be observed in ammeter. So the least value will be varying depending upon its range. If we consider the range of ammeter is 30 A and the scale readings are 10 numbers, then the least value will be 30/10 = 3 A per scale.
So the least value is determined as 
So among the given options 0.1 is most suitable for an ammeter with range of 3 A with 30 divisions.
Answer:

Explanation:
Take at look to the picture I attached you, using Kirchhoff's current law we get:

This is a separable first order differential equation, let's solve it step by step:
Express the equation this way:

integrate both sides, the left side will be integrated from an initial voltage v to a final voltage V, and the right side from an initial time 0 to a final time t:

Evaluating the integrals:

natural logarithm to both sides in order to isolate V:

Where the term RC is called time constant and is given by:

Answer:
65.9°
Explanation:
When light goes through air to glass
angle of incidence, i = 35°
refractive index, n = 1.5
Let r be the angle of refraction
Use Snell's law


Sin r = 0.382
r = 22.5°
Now the ray is incident on the glass surface.
A = r + r'
Where, r' be the angle of incidence at other surface
r' = 60° - 22.5° = 37.5°
Now use Snell's law at other surface

Where, i' be the angle at which the light exit from other surface.

Sin i' = 0.913
i' = 65.9°
Answer:
B
Explanation:
because it would change the direction and speed
Air resistance could be acting on the object