Answer:
Hiiiiiiii........where r u frm??
Answer:
Constructive interference
Explanation:
Here, the medium is same, same wavelength, same frequency, same amplitude and same direction of propagation.
Let the intensity of waves be I which is same for both
The formula for the net intensity is

where, Ф be the phase difference
So, 
Here, IR is maximum so the interference is constructive in nature.
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:

Initial volume of mercury is
V = 0.1 cm³
The temperature rise is 35 - 5 = 30 ⁰C = 30 ⁰K.
Because the coefficient of volume expansion is 1.8x10⁻⁴ 1/K, the change in volume of the mercury is
ΔV = (1.8x10⁻⁴ 1/K)*(30 ⁰K)(0.1 cm³) = 5.4x10⁻⁴ cm³
The cross sectional area of the tube is
A = 0.012 mm² = (0.012x10⁻² cm²).
Therefore the rise of mercury in the tube is
h = ΔV/A
= (5.4x10⁻⁴ cm³)/(0.012x10⁻² cm²)
= 4.5 cm
Answer: 4.5 cm