# Electromagnetism MCQ

1. What is the magnetic field outside a solenoid?

A. Infinity
B. Half the value of the field inside
C. Double the value of the field inside
D. Zero

There are no magnetic lines of force outside a solenoid, hence the magnetic field outside a solenoid is zero.

Scalars and Vectors in physics

2. Which, among the following qualities, is not affected by the magnetic field?

A. Moving charge
B. Change in magnetic flux
C. current flowing in a conductor
D. Stationary charge

A stationary charge is not affected by a magnetic field because stationary charges do not have any velocity. The magnetic field cannot occur in a particle having zero velocity.

3. When a charged particle moves at right angles to the magnetic field, the variable quantity is?

A. Momentum
B. Speed
C. Energy
D. Moment of inertia

When a charged particle moves perpendicular to the field, its speed remains the same whereas its velocity keeps on changing.

Momentum is the product of the mass of the particle and the velocity of the particle, hence since velocity varies, momentum also varies.

4. If the flow of electric current is parallel to the magnetic field, the force will be ______

A. Zero
B. Infinity
C. Maximum
D. Half the original value

Force is a cross-product. A cross product involves the sine of the angle between them. If two quantities are parallel to each other, the angle between them is zero. Sin(0) is zero, hence force is zero.

5. The ratio of magnetic force to electric force on a charged particle getting undeflected in a field is?

A. 1
B. 0
C. 2
D. 4

When a charged particle is undeflected in a field, the magnitude of the magnetic force and electric force acting on the particle is the same, hence the ratio is 1.

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6. What is the strength of the magnetic field known as ________

A. Flux
B. Density
C. Magnetic strength
D. Magnetic flux density

The strength of the magnetic field is also known as magnetic flux density. It is the number of magnetic field lines crossing the unit area.

7. Weakest force in nature is?

A. Electric force
B. Gravitational force
C. Weak force
D. Magnetic force

Gravitational force is the weakest force in nature as it does not bind anything strongly with its help.

8. How can a magnetic field be produced?

A. Using a permanent magnet
B. Electric current
C. Using a temporary magnet
D. Using a permanent magnet or electric current

An electric current, as well as the permanent magnet, produces a magnetic field whereas a temporary magnet fails to do so.

9. Can we see magnetic flux lines?

A. Yes
B. No
C. Depends on the strength of the field
D. Only when the field strength is very large

No, we cannot see magnetic flux lines as the “lines of magnetic flux” is purely an imaginary concept to understand the magnetic field clearly.

10. Magnetic Field lines move from _______

A. North to south
B. South to north
C. West to east
D. East to west