PHYS040C FINAL

A point charge Q is located a short distance from a point charge 3Q, and no other charges are present. If the electrical force on Q is F, what is the electrical force on 3Q?

F

An electromagnetic wave propagates along the +y direction as shown in the figure. If the electric field at the origin is along the +z direction, what is the direction of the magnetic field?

+x

Four equal negative point charges are located at the corners of a square, their positions in the xy plane being (1,1),(-1,1),(-1,-1),(1,-1). The electric field on the x-axis at (1,0) points in the same direction as...

-i

If the magnetic field of an electromagnetic wave is in the +x direction and the electric field of the wave is in the +y direction, the wave is traveling in the...?

-z direction

When an electromagnetic wave falls on a white, perfectly reflecting surface, it exerts a force F on that surface. If the surface is now painted a perfectly absorbing black, what will be the force that the same wave will exert on the surface?

F/2

The charge on the square plates of a parallel-plate capacitor is Q. The potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. The amount of charge on the plates is now equal to

Q/2

Two capacitors, C1 and C2, are connected in series across a source of potential difference. With the potential source still connected, a dielectric is now inserted between the plates of capacitor C1. What happens to the charge on capacitor C2?

The charge on C2 increases

A long straight conductor has a constant current flowing to the right. A wire rectangle is situated above the wire, and also has a constant current flowing through it (as shown in the figure). Which of the following statements is true?

The net magnetic force on the wire rectangle is downward, and the net torque on it is zero.

Lenz's Law

There is an induced current in closed, conducting loop if and only if the magnetic flux through the loop is changing. The direction of the induced current is such that the induced magnetic field oppose the change in flux.

A circular loop of wire lies in the plane of the paper. An increasing magnetic field points out of the paper. What is the direction of the induced current in the loop?

clockwise

A circular loop of wire lies in the plane of the paper. An increasing magnetic field points out of the paper. What is the direction of the induced current in the loop

clockwise

A closed, circular loop has a counterclockwise current flowing through it as viewed by the person on the right. If a second closed circular loop with the same radius approaches this loop with constant velocity along a common axis as shown, in what direction will a current flow in the approaching loop as viewed by the person on the right?

clockwise

A charged particle is moving with a speed v perpendicular to a uniform magnetic field. A second identical charged particle is moving with speed 2v perpendicular to the same magnetic field. If the frequency of revolution of the first particle is f, the frequency of revolution of the second particle is...

f

In the figure, the inner loop carries a clockwise current I that is increasing. The resistor R is in the outer loop and both loops are in the same plane. The induced current through the resistor R is

from left to right across the resistor

Which one of the phasor diagrams shown below best represents a series LRC circuit driven at resonance?

in resonance, the voltage from the inductor and the voltage from the capacitor will cancel each other and the voltage across the resistor is what matters

The three loops of wire shown in the figure are all subject to the same uniform magnetic field B that does not vary with time. Loop 1 oscillates back and forth as the bob in a pendulum, loop 2 rotates about a vertical axis, and loop 3 oscillates up and down at the end of a spring. Which loop, or loops, will have an emf induced in them?

loop 2 only

A current carrying loop of wire lies flat on a table top. When viewed from above, the current moves around the loop in a counterclockwise sense. For points OUTSIDE the loop, What is the magnetic field caused by this current?

points straight down.

A capacitor is charging in a simple RC circuit with a dc battery. Which one of the following statements about this capacitor is accurate?

there is a magnetic field between the capacitor plates, even though no charge travels between them, because the electric flux between the plates is changing

A negatively charged particle is moving to the right, directly above a wire having a current flowing to the right, as shown in the figure. In which direction is the magnetic force exerted on the particle?

upward