Electromagnetic Effects

Multiple Choice

Using the right hand grip rule for a straight wire, A represents the direction of the

• current

• magnetic field

Multiple Choice

Using the right hand rule for a straight wire, B represents the direction of the

• current

• magnetic field

Multiple Choice

If the current is going up on the front side of the coil then what side of the electromagnet is north?

• Up
• Down
• Left
• Right

Multiple Choice

What is the direction of the current in this wire and what is the direction of the field above the wire?

• left, out of the page
• left, into the page
• right, out of the page
• right, into the page

Multiple Choice

Refer the diagram. A wire carries a current, creating a magnetic field around itself as shown. The current in the wire is:

• Directed to the right

• Directed to the left

• Equal to the magnetic field

• n the same direction as the magnetic field

Multiple Choice

Refer the diagram. The right face of the loop acts as North pole and left side of loop acts as south pole

• False

• True

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Multiple Choice

What direction does the wire move?

• Up

• Down

• Left

• Right

Multiple Choice

What direction would the wire move? (What direction does the force act?)

• Up

• Down

• Left

• Right

Multiple Choice

What direction would the wire move?

• Up

• Down

• Left

• Right

Multiple Choice

The diagram show the direction of magnetic field,B and current, I.

By using Fleming left hand rules, determine the direction of Magnetic force, F.

• no force produced

• right

• into the page

• out from the page

Multiple Choice

The diagram show the direction of magnetic field,B and current, I.

By using Fleming left hand rules, determine the direction of Magnetic force, F.

• no force produced

• downward

• into the page

• out from the page

Multiple Choice

The diagram show the direction of magnetic field,B and velocity,v of an electron.

By using Fleming left hand rules, determine the direction of Magnetic force, F.

• left

• right

• into the page

• out from the page

Multiple Choice

What must be the angle between the wire and the magnetic field to experience the full force?

• 45 degrees

• 90 degrees

• 0 degrees

• 180 degrees

Word Cloud

One use of a motor

Multiple Choice

A coil carries a current in a magnetic field. The coil experiences a turning effect.

Which device uses this effect?

• a d.c. motor

• an electromagnet

• a relay

• a transformer

Multiple Choice

The diagram shows a flat, rectangular coil placed between the poles of a magnet.

There is a current in the coil that makes it turn in the direction shown in the diagram.

Which change would make the coil turn in the opposite direction?

• decreasing the current in the coil

• increasing the number of turns on the coil

• reversing both the direction of the current in the coil and the poles of the magnet

• reversing only the direction of the current in the coil

Multiple Choice

A current-carrying coil in a magnetic field experiences a turning effect.

How can the turning effect be increased?

• Reduce the size of the current.

• Increase the number of turns on the coil.

• Use thinner wire for the coil.

• Reverse the direction of the magnetic field.

Multiple Choice

-

• A

• B

• C

• D

Multiple Choice

What is the function of a split ring commutator?

• To increase the speed of the motor.
• To provide electrical insulation between coils.
• To generate a magnetic field in the motor.
• To reverse the direction of current in the coil of a motor

Multiple Choice

What is the direction of the rotation?

• Clockwise

• Anticlockwise

• Downward
• Upward

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Multiple Choice

A magnet is suspended from a spring so that it can move freely inside a stationary coil. The coil is

connected to a sensitive centre-zero galvanometer.

The magnet repeatedly moves slowly up and down.

What does the galvanometer show?

• a constantly changing reading

• a steady reading to the left

• a steady reading to the right

• a steady reading of zero

Multiple Choice

A student investigates electromagnetic induction. She has a bar magnet and a coil of wire that is

connected to a sensitive ammeter.

Which movement does not cause a reading on the ammeter?

• moving the magnet to the left

• moving the coil to the right

• moving both the magnet and the coil to the left at the same speed

• moving both the magnet and the coil towards each other at the same speed

Multiple Choice

The diagram shows a coil of wire connected to a voltmeter.

A student has a magnet and an unmagnetised iron rod.

How can an e.m.f. be induced across the coil?

• holding the magnet inside the coil

• holding the iron rod inside the coil

• pushing the magnet into the coil

• pushing the iron rod into the coil

Multiple Choice

What type of current is being produced?

• Alternating

• Direct

Multiple Choice

The production of electric current by a changing magnetic field is called ____________________________________.

• induced current

• electromotive force

• electromagnetic induction

• internal resistance

Multiple Choice

Which rule do we use to predict the direction a current carrying wire will move in a magnetic field?

• Fleming's Left Hand Rule
• Fleming's Right Hand Rule
• Faraday's Left Hand Rule
• Faraday's Right Hand Rule

Multiple Choice

Magnetic field produced around a straight conductor due to current in it is given by

• Fleming's right hand rule

• Right hand grip rule

• Clock rule

• Fleming's left hand rule

Multiple Choice

What direction should the induced current flow?

• Upwards

• Into the page/screen

• Downwards

• Out of the page/screen

Multiple Choice

What is the direction of the induced current around the whole circuit?

• Clockwise

• Alternating

• Anticlockwise

• No current induced

Multiple Choice

A coil carries a current in a magnetic field. The coil experiences a turning effect.

Which device uses this effect?

• a d.c. motor

• an electromagnet

• a relay

• a transformer

Multiple Choice

An e.m.f. is induced across a wire when it moves through the magnetic field between the poles of

a magnet.

Which electrical device operates because of this effect?

• a battery

• a cathode-ray tube

• a generator

• a motor

Multiple Choice

Which device uses slip rings?

• a d.c. electric motor

• a relay

• a transformer

• an a.c. generator

Multiple Choice

No EMF is induced when?

• When the wire is not moving

• When the wire is moving parallel to magnetic field direction

• When no lines are cut by the wire

• all of the above

Multiple Choice

When there is a change in the magnetic field in a closed loop of wire

• (a) a voltage is induced in the wire
• (b) current is made to flow in the loop of wire 
• (c) electromagnetic induction occurs
• (d) all of these

Multiple Choice

Which of the following increases frequency of AC?

• increasing number of turns on the coil

• using a stronger magnet

• rotating the coil faster

• increase area of the coil

Multiple Choice

What will be the direction of the induced current in a generator when the direction of the motion is upwards while the magnetic flux is to the right?

• To the left

• Upwards

• Towards

• Away

Open Ended

How is electricity delivered to houses?

​Have you ever seen this sign?

Multiple Choice

The function of a transformer is to ...

• raise and lower the apparent power levels

• transfer DC voltage from the primary winding to the secondary winding

• increase or decrease A.C voltage or A.C current levels

• transform mechanical energy into electrical energy

Multiple Choice

Assume primary has 240 turns and secondary has 60 turns. Primary is connected with 120V AC power supply. What is the voltage on the secondary?

• 30 V

• 0.333 V

• 2 V

• 120V

Multiple Choice

This picture is an example of a ___________

• Step- Up Transformer
• Step- Down Transformer
• Motor
• Generator

Multiple Choice

A transformer does not change the following:

• Frequency

• Voltage

• Current

• None of these

Multiple Choice

If the primary power of an ideal transformer having a 2:1 voltage ratio is 100 W, the secondary power is:

• 200 W

• 75 W

• 50 W

• 100 W

Open Ended

A 12Ω resistor is connected across the secondary winding of an ideal transformer whose secondary voltage is 120V. Determine the primary voltage if the supply current is 4A.

Multiple Choice

Will a transformer work with direct current (d.c.) or alternating current (a.c.)?

• a.c. only
• d.c. only
• Both a.c. and d.c.