C) alternating current .
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B)direct current </span>
Answer:
Electric potential = 0.00054 V
Explanation:
We are given;
Charge; q = 3 pC = 3 × 10^(-12) C
Radius; r = 2 cm = 0.02 m
Formula for the electric potential of this surface will be;
V = kqr
Where;
K is a constant = 9 × 10^(9) N⋅m²/C².
Thus;
V = 9 × 10^(9) × 3 × 10^(-12) × 0.02
V = 0.00054 V
Since there is no friction between the ladder and the wall, there can be no vertical force component. That's the tricky part ;)
So to find the weight, divide the 100N <em>normal</em> force by earths gravitational acceleration, 9.8m/s^2

Then;
Draw an arrow at the base of the ladder pointing towards the wall with a value of 30N, to show the frictional force.
Answer:
- path differnce = 2.18*10^-6
- 1538 lines
Explanation:
- The path difference for the waves that produce the pattern of diffraction, is given by the following formula:
(1)
d: separation between slits = 0.50mm = 0.50*10^-3 m
θ: angle of a diffraction = 0.25°
Then, the path difference is:

- The maximum number of bright lines are calculated by using the following formula:
(2)
m: order of the bright
λ: wavelength = 650nm
The maximum bright is calculated for an angle of 90°:

The maxium number of bright lines are twice the previous result, that is, 1538 lines