Answer:
(A) Speed will be 
(b) Change in kinetic energy =
Explanation:
We have given mass of proton 
Acceleration of the proton 
Initial velocity u =
m/sec
Distance traveled by proton s = 3.90 cm = 0.039 m
(a) From third equation of motion we know that



(b) Initial kinetic energy 
Final kinetic energy 
So change in kinetic energy 
The correct answer is: <span>Unscrew one light, if the others remain on it is a parallel circuit.</span>