Technically, it's a wedge choice letter D.
Answer:
Explanation:
When two coherent light beams travel different paths and arrive at a point , there will be difference in the length of path travelled by them . If this difference is zero then both will reinforce each other and their brightness will add up . Hence there will be constructive interference .
If their path difference is not zero but it is equal to odd multiple of their half wavelength like λ / 2 , 3 λ / 2 , 5 λ /2 , 7 λ /2 etc , then instead of reinforcing each other , they will destroy each other . This is called destructive interference . As a result of it , darkness will prevail at the point where they meet or interfere.
Answer:
The internal resistance of the cell is 0.051 ohm.
Explanation:
Given;
emf of the battery, E = 12 V
terminal voltage of the cell, V = 8.2 V
current in the circuit, I = 75 A
let the potential drop of the cell due to internal resistance (r) = Ir
The internal resistance of the cell is calculated from the equation below;
E = V + Ir
where;
r is the internal resistance of the cell

Therefore, the internal resistance of the cell is 0.051 ohm.
Answer: Its the last one: The position of the block will change
Explanation: Since the forces are unbalanced, one side of the block will be stronger, therefore making the block move.
Answer:
-0.0426 m
Explanation:
-i / o = h' / h
-1.71 / 0.0237 = 3.04 /o
o = -0.042
1/o + 1/i = 1/f
1/(-0.042) + 1/(3.04) = 1/f
-23.81 +0.329 = 1/f
-23.481 = 1/f
f = -0.0426 m