IAL Physics Unit 2 Revision

Laser light is shone through a diffraction grating so that a series of bright dots appears on a screen. Which is correct?

• The diffraction grating is set up so that it is parallel to the screen.
• The angle θ is measured using a protractor.
• The diffraction grating is set up so that it is parallel to the laser light beam.
• The distance between the bright dots is measured with a micrometer.

Two copper wires are placed in series in a complete circuit. The electrons in the two wires have different values of drift velocity. Which of the following must be different for the two wires?

• current
• cross-sectional area
• charge carrier density
• length

Waves can be represented on graphs of displacement against distance and displacement against time. Which of the following properties can only be determined by combining information from both graphs?

• amplitude
• speed
• frequency
• wavelength

The equation I = nqvA relates the current in a sample of a material to the movement of free charge carriers in the sample. Which is correct?

• q represents the total charge stored in the sample.
• n represents the number of charge carriers in the sample.
• v represents the drift velocity of the charge carriers in the sample.
• A represents the surface area of the sample.

A student investigates how different variables affect the speed of waves on a vibrating string. Which of the following would increase the speed of waves along the string?

• increasing the length of the string
• increasing the mass per unit length of the string
• increasing the frequency
• increasing the tension in the string

The definitions for current and potential difference both include

• resistance.
• work done.
• time.
• charge.

Ultrasound has a number of different uses in medicine. Which of the following is the main reason why ultrasound is not used to perform scans of the chest and lungs?

• The air in the lungs causes most of the ultrasound to be reflected back.
• The wavelength of the ultrasound is too long.
• The duration of the pulses of ultrasound limits the amount of detail that can be seen.
• Ultrasound can damage the lungs.

The resistance of some electrical components decreases as the applied potential difference increases. Choose the correct pair.

• diode and ohmic conductor
• negative temperature coefficient thermistor and diode
• ohmic conductor and filament lamp
• filament lamp and negative temperature coefficient thermistor

Ultrasound scans can be used to create an image of a patient's kidneys. For each ultrasound pulse sent into the body, a number of pulses are detected. Why are a number of pulses detected?

• Interference occurs when the pulse is in the body.
• The ultrasound has a very high frequency.
• The ultrasound has a very large wavelength.
• The ultrasound reflects off different layers within the body.

Two copper wires of identical cross-sectional area are placed in series in a circuit. Which of the following could be different for the two wires?

• charge carrier density
• drift velocity
• potential difference
• current