QUESTIONS AND ANSWERS 2025
Magnetic fields cannot have - ANSWER-monopoles.
An object is at a position 2.0 cm from a converging lens with a focal length of 3.0 cm.
The image is best described as - ANSWER-Virtual Upright
Electric fields direct - ANSWER-away from positive charges and towards negative
charges.
Electromagnetic waves deliver - ANSWER-an oscillating amount of energy to a given
area of space each second.
Induced emf is proportional to - ANSWER-the rate of change of flux.
A particular inductor is connected to a circuit where it experiences a change in current
of 0.8 amps every 0.10 sec. If the inductor has a self-inductance of 2.0 V, what is the
inductance? - ANSWER-0.25H
Which of the following circuit components will function the same regardless of whether
the voltage source is direct or alternating? - ANSWER-Resistors
A magnetic field oscillates in the +/-z direction, while the electric field oscillates in the +/-
y direction. The direction of the wave motion is - ANSWER-In the X direction
A particular electromagnetic wave has a frequency of 5 x 1017 Hz. What is the
wavelength of the wave? - ANSWER-6 x 10^-10 m
Which of the following statements regarding radio waves and sound waves is accurate?
- ANSWER-Sound waves are transverse waves.
Sound waves and radio waves travel at approximately the same speed.
Neither sound waves or radio waves can travel through water.
xxxxx None of the above statements are accurate.
Red light has a wavelength of 6.5 x 10-7 m. What is the frequency of red light? -
ANSWER-4.6 x 1014 Hz
The reason why humans cannot see infrared waves is because? - ANSWER-The waves
are too long for human eyes to detect.
, What is the intensity of an electromagnetic wave that delivers 3000 joules of energy to a
0.5 m2 area every 3.0 sec? - ANSWER-2000 W/m2
A particular electromagnetic wave has a peak magnetic field strength of 5 x 10-5 T.
What is the average intensity of the electromagnetic wave? - ANSWER-2.99 x 10^5
W/m^2
What is the purpose of a transformer? - ANSWER-Transformers change the voltage in a
circuit.
What is the peak electric field strength of an EM wave if the peak magnetic field
strength is 0.1 T? - ANSWER-3 x 10^7 N/C
The length of a linear broadcasting antenna is oriented in the y plane. A linear receiving
antenna should be oriented in the - ANSWER-Y plane
Wave intensity is defined as the? - ANSWER-Rate of energy delivered to a certain area.
A wire loop moves into a magnetic field as shown below. Which of the following will
result? (Moving to the right, half in the field, magnetic field going into the screen) -
ANSWER-This will induce a counterclockwise current in the loop.
What is the electric field strength of an EM wave if the peak intensity of the wave is
5000 W/m2? - ANSWER-1372 W/m2
The speed of an electromagnetic wave depends on? - ANSWER-none of the above
A wire loop sits motionless in a uniform magnetic field as shown below. Which of the
following changes will induce a clockwise current in the loop? (fully in the field, field
pointing out of the screen) - ANSWER-Increase the magnetic field strength.
A 15-turn circular wire loop with a radius of 3.0 cm is initially in a uniform magnetic field
with a strength of 0.5 T. The field decreases to zero over a time of 0.10 sec. What is the
induced emf? - ANSWER-0.21V
The primary difference between x-ray waves and radio waves is - ANSWER-X-Ray
waves are higher frequency
What is the peak magnetic field strength of an EM wave if the peak electric field
strength is 3500 T? - ANSWER-1.2 x 10^-5 T
Which of the following is a true statement? - ANSWER-Electric fields direct away from
positive charges and towards negative charges.
Which of the following factors will affect the intensity of an EM wave? - ANSWER-
Amplitude