Answer:
A drop in voltage occurs
Explanation:
When electric current flows through a conduct, there are three basic electrical effects that occur to the conductor;
1. A magnetic field is set up around the conductor,
A magnetic field is formed around a conductor when current flows through it which makes it acts like a magnet. Application is used in electric bells.
2. Heat is generated, and
The heating effect of current is due to the conversion of some of the electrical energy that passes through the conductor, into heat energy. Application of heat effect include electric iron, microwave oven, electric bulb, hair straightener etc.
H = I²Rt
3. A drop in voltage occurs
Voltage drop is as a result of current passing through the impedance offers by the conductor or circuit elements. When current passes through a conductor, the resistance offers opposition to the flow of the electric current according to Ohm's law.
Answer:
The width of the central bright fringe on the screen is observed to be unchanged is 
Explanation:
To solve the problem it is necessary to apply the concepts related to interference from two sources. Destructive interference produces the dark fringes. Dark fringes in the diffraction pattern of a single slit are found at angles θ for which

Where,
w = width
wavelength
m is an integer, m = 1, 2, 3...
We here know that as
as w are constant, then

We need to find
, then

Replacing with our values:


Therefore the width of the central bright fringe on the screen is observed to be unchanged is 