Differences:
An electrical motor converts electrical energy into mechanical energy,where as a generator converts mechanical energy into electrical energy.
The principle of a electric motor if there is a change of the magnetic field across a conductor electrons are forced to move in a direction perpendicular to the direction of the magnetic field,where as in a generator if a charge is moving in a magnetic field, a force acts on the charge in a direction perpendicular to both the velocity of the charge and the magnetic field.
similarities:
Both electric motor and generator work on the magnetic effects of electric current.
Both have the armatures to rotate the loop.
Answer:
0.23348 A
Explanation:
B = Magnetic field
v = Velocity of electron = 
q = Charge of electron = 
= Vacuum permeability = 
r = Radius of circle = 0.026 m
N = Number of turns = 103 turns/cm = 
I = Current
The magnetic and centripetal force will be balanced

The magnetic field in solenoid is given by

From the first equation

The current in the solenoid is 0.23348 A
Answer: Option A: The number of trees sampled.
The accuracy can be understood as how close is the measured value to the true value. The aim is to monitor the population size of the insect pest in a 50 square kilometer. Random trees are selected, and number of eggs and larvae are counted. So, the measured value would be closer to actual value when the number of trees sampled are increased. More the number of trees sampled, less would be the chances of error and the accuracy of the estimate would increase.
Mass = Volume/Density. The answer is 9.8kg