Physics quizzes

A circular coil of 20 turns and radius 5.0 cm is placed with its plane oriented at 90° to a uniform magnetic field of 0.10 T. The field is now increased at a steady rate, reaching a value of 0.50 T after 4.0 seconds. What emf is induced in the coil?

) 0.016 V

A circular coil lies flat on a horizontal surface. A bar magnet is held above the center of the coil with its north pole pointing down. If the magnet is dropped from this position what is the direction of the induced current in the coil, as viewed from above?

) counterclockwise

A light beam has speed c in vacuum and speed v in a certain plastic. The index of refraction n of this plastic is

) n = c/v.

. Which one of the following expressions is the correct representation for the speed of light in vacuum?

1 / √ε0µ0

A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the highest frequency associated with this portion of the spectrum?

1.50 × 1015 Hz

A battery maintains the electrical potential difference of 3.0 V between two large parallel metal plates separated by 3.0 mm. What is the strength of the electric field between the plates?

1000 V/m

A thin flashlight beam traveling in air strikes a glass plate at an angle of 52° with the plane of the surface of the plate. If the index of refraction of the glass is 1.4, what angle will the beam make with the normal in the glass?

26°

A small bead, sitting at the origin, has a charge of +10nC. At the point (3.0cm, 4.0cm), what is the magnitude of the electric field due to this bead?

36000 N/C

1. A certain metal wire has a diameter of 1 cm and a resistivity of 1.7 × 10-8 Ω ∙ m. How long would it have to be to have a resistance of 1.0 Ω?

4.6 × 103 m

An optic fiber is made of clear plastic with an index of refraction of 1.50. For what range of angles of incidence θ with the lateral surface of the fiber will light remain inside the plastic "guide" if it is surrounded by air?

41.8° < θ < 90°

. A very long straight current-carrying wire produces a magnetic field of 20 mT at a distance d from the wire. To measure a field of 5 mT due to this wire, you would have to go to a distance from the wire of

4d.

Two long parallel wires carry currents of 20 A and 5.0 A in opposite directions. The wires are separated by 0.20 m. What is the strength of the magnetic field midway between the two wires?

5.0 × 10-5 T

1. A light bulb operating at 110 V draws 1.40 A of current. What is its resistance?

78.6 Ω

The electric potential inside a parallel-plate capacitor

Increases linearly from the negative to the positive plate

Two point charges, q1 and q2, are separated by a distance R. If the magnitudes of both charges are halved and their separation is also halved, what happens to the electrical force that each charge exerts on the other one?

It remains the same.

As shown in the figure, a metal bar is in contact with a pair of parallel rails and is in motion with an upward velocity of magnitude ν. A uniform magnetic field is present, directed downward as shown. The direction of the induced current through the resistor R is

No current is induced.

What properties about the resistors in this circuit are the same for all three? (Parallel Circuit)

Potential Difference

Which of the three right-hand charges experiences the largest force?

q and 4q are tied

In an RLC ac circuit, the values of the inductance and capacitance are both doubled. As a result of this change, the resonance frequency of the circuit is

reduced to one-half the original value

A ring with a clockwise current (as viewed from above the ring) is situated with its center directly above another ring, which has a counter-clockwise current, as shown in the figure. In what direction is the net magnetic force exerted on the top ring due to the bottom ring?

upward