Voltmeter is used to find the potential difference between two points.
We always connect it in parallel to the points where we need the potential difference.
Here in order to make the reading accurate we can increase the resistance of voltmeter so that it can not withdraw any current from the circuit.
Answer
given,
wavelength (λ)= 500 n m
thickness of film= 10⁻⁴ cm
refractive index = μ = 1.375
distance traveled is double which is equal to 2 x 10⁻⁴ cm
a) Number of wave
N = 2.91
N = 3
b) phase difference is equal to
Reflection from the first surface has a 180° (½λ) phase change.
There is no phase change for the 2nd surface reflection and there is no phase difference for the 2nd wave having traveled an exact whole number of waves.
net phase difference = 
= 270°
the answer is c) the speed and direction of travel must be constant
<h2>
Entire trip takes 1.22 seconds.</h2>
Explanation:
We have equation of motion s = ut + 0.5 at²
Initial velocity, u = 0 m/s
Acceleration, a = 9.81 m/s²
Time, t = 0.866 s
Substituting
s = ut + 0.5 at²
s = 0 x 0.866 + 0.5 x 9.81 x 0.866²
s = 3.68 m
Halfway is 3.68 m
Total height = 2 x 3.68 = 7.36 m
We have equation of motion s = ut + 0.5 at²
Initial velocity, u = 0 m/s
Acceleration, a = 9.81 m/s²
Time, t = ?
Displacement, s = 7.36 m
Substituting
s = ut + 0.5 at²
7.36 = 0 x t + 0.5 x 9.81 x t²
t = 1.22 s
Entire trip takes 1.22 seconds.
