Conceptual
An electromagnetic wave travels through air. If the electric field is pointing West and the wave is traveling down, what direction is the magnetic field pointing?
North (found using the right hand rule: index finger is electric field, fingers bent at right angle are magnetic field, and thumb is direction of propagation)
You have a collection of resistors, each with identical resistance R.
a) If you connect the resistors in series, will the equivalent resistance be less than R, greater than R, or equal to R?
b) If you connect the resistors in parallel, will the equivalent resistance be less than R, greater than R, or equal to R?
a) greater than R
b) less than R
What is the sound level in dB of a sound with a frequency of 519 Hz and an intensity of 3.12 x 10^-6 W/m^2, on a day when the speed of sound in air is 343 m/s?
64.9 dB
A string is fixed at both ends. In its third harmonic (second overtone) it vibrates with a frequency of 396 Hz.What is the fundamental frequency of vibration on this string?
132 Hz
Light travels from an unknown substance with index of refraction n into air. The critical angle for total internal reflection is theta in this case. Glass has a larger index of refraction than the unknown substance. If light travels from glass into air, what is true for the critical angle in this case?
The critical angle is smaller than theta
A resistor with resistance R has a current I0 through it when a potential difference (voltage) V0 is held across it, and dissipates power P0. The voltage is then decreased.
a) Will the current through the resistor increase, decrease, or stay the same?
b) Will the power dissipated by the resistor increase, decrease, or stay the same?
a) decrease
b) decrease
What is the beat frequency of Sound A at 630 Hz and Sound B at 675 Hz?
45 Hz
Use the drawing of capacitors to find the equivalent capacitance of this system of capacitors. C1 = 4.18 muF, C2 = 2.23 muF, and C3 = 4.61 muF.
5.68 muF
You look at an image of yourself in a spherical mirror. The image is real. Is the image upright or inverted? Is the mirror concave or convex?
The image must be inverted, and the mirror must be concave.
You are given a parallel-plate capacitor, made of two plates with area A and initially separated by a distance d. They are connected to a 7V source of ideal emf. You halve the distance between the plates while it is connected to the battery.
a) Will the capacitance increase, decrease, or stay the same?
b) Will the charge on the plates increase, decrease, or stay the same?
a) increase
b) increase
The drawing provided shows light incident from air (index of refraction 1.00) into a block of transparent plastic, with index of refraction n=1.52. Some of the light reflects back into air, and some refracts into the plastic. Theta1 = 32.6 degrees is the angle of the incident light with respect to the normal in air, and theta2 is the angle of the refracted beam wit respect to the normal in the plastic. Theta3 is the angle of the light reflected back into air at the surface.
a) What is the refracted angle theta2?
b) What is the reflected angle theta3?
c) What is the speed of light in this plastic?
a) 20.8 degrees
b) 32.6 degrees
c) 1.97e8 m/s
What is the charge on a capacitor of 4.18 muF when the potential difference across the capacitor is 2.68 V?
11.2 muC
In a double slit experiment, you use a double slit with slit spacing d. The first-order maximum for light of wavelength 456 nm appears at an angle of 26 degrees.
a) Will the second-order maximum for this light appear at an angle greater than, less than, or equal to 26 degrees?
b) Will the first-order maximum for light of wavelength 300 nm be an angle greater than, less than, or equal to 26 degrees?
c) If you replace the double slit with a different double slit with spacing 0.5d, will the first order maximum for light of wavelength 456 nm be greater than, less than, or equal to 26 degrees?
a) greater than 26 degrees
b) less than 26 degrees
c) greater than 26 degrees
Two loudspeakers are emitting sound of exactly the same frequency and exactly in phase. Speaker 1 is on a truck, traveling quickly towards you. Speaker 2 is at rest on the ground.
a) If you stand at rest on the ground and listen to the speakers, which sounds to you like it has a higher frequency?
b) If the truck speeds up, what would happen to the beat frequency you hear?
a) The sound from speaker 1
b) it should increase
You look through a converging lens at a coffee mug. The mug is 1.32 m away from the lens. You see an image of the mug a distance of 0.450m away from the lens. The image is inverted. What is the magnification and focal length of the lens?
magnification: -0.341
focal length: 0.336 m
A 221 Ohm resistor is composed of a material with resistivity 1.14E-6 ohm*m. If the resistor is made of a cylindrical wire with radius 1.23E-4 m, what is the length of the wire?
9.21 m
There is a uniform electric field in a region of space. The electric field is point to the right. There are 2 points, A and B. A is located to the left of B.
a) At which point would an electron have a higher potential energy?
b) Which point has a higher electric potential?
a) B
b) A
A builder is designing a pipe organ. There are two pipes of equal length, but one is open at both ends, while the other has one open end and one closed end. They are both at the same air temperature and pressure.
a) Which pipe will have a longer wavelength corresponding to its fundamental frequency?
b) Which pipe will have a higher fundamental frequency?
a) the pipe with one open and one closed end
b) the pipe that is open at both ends
Polarized light with intensity 1.63 W/m^2 passes through another polarizer that is oriented at 35.8 degrees from the first polarizer. What is the intensity of the light after passing through the second polarizer?
1.07 W/m^2