On-going Assessment

A 150 W transformer has an input potential difference of 9.0 V and an output current of 5.0 A. What is the ratio of V_output to V_input?

• 1 to 3

• 3 to 1

• 3 to 10

• 10 to 3

A transformer uses a 91 V supply to operate a 13 V device. If the transformer has 130 turns on the primary coil and the device uses 1.9 A of current from the transformers, what is the current supplied to the primary coil?

• 0.27 A

• 0.70 A

• 4.8 A

• 13.3 A

For a charged particle moving in a circular trajectory,

• the magnetic force is parallel to the velocity and is directed toward the center of the circular path.

• the magnetic force may be perpendicular to the velocity and is directed away from the center of the circular path.

• the magnetic force always remains parallel to the velocity and directed away from the center of the circular path.

• the magnetic force always remains perpendicular to the velocity and is directed toward the center of the circular path.

Rays emitted by cathode-ray tube are:

• Light

• Radiations

• Signals

• Electrons

The forces that are balanced in the cathode-ray tube are:

• Magnetic Force & Nuclear Force

• Electric Force & Magnetic Force

• Electric Force and Nuclear Force

• Magnetic Force & Gravitational Force

What did J.J. Thomson discover

• proton

• nucleus

• electron

• neutron

An EMF and current in one coil due to changing current in another coil is called:

• Self-inductance

• Mutual inductance

• step-up transformer

• step-down transformer

Induced EMF in a step-up transformers decreases voltage for consumer use.

• True

• False

Which of the following transformers has the lowest induced current in the secondary coil:

• a primary coil of 50 turns, and secondary coil of 25 turns, and primary current: 2 A

• a primary coil of 50 turns, and secondary coil of 60 turns, and primary current: 2 A

• a primary coil of 20 turns, and secondary coil of 10 turns, and primary current: 4 A

• a primary coil of 20 turns, and secondary coil of 40 turns, and primary current: 8 A

• a primary coil of 10 turns, and secondary coil of 100 turns, and primary current: 1 A

Which of the following transformers has the greatest induced current in the secondary coil:

• a primary coil of 50 turns, and secondary coil of 25 turns, and primary current: 2 A

• a primary coil of 50 turns, and secondary coil of 60 turns, and primary current: 2 A

• a primary coil of 20 turns, and secondary coil of 10 turns, and primary current: 4 A

• a primary coil of 20 turns, and secondary coil of 40 turns, and primary current: 8 A

• a primary coil of 10 turns, and secondary coil of 100 turns, and primary current: 1 A