Free Printable Topic 9 IB Physics

1.

Which of the following is the correct expression for the displacement x?

a)

$-x_0\cdot\cos\ \frac{2\pi}{T}t$

b)

$x_0\cdot\cos\ \frac{2\pi}{T}t$

c)

$-x_0\cdot\sin\ \frac{2\pi}{T}t$

d)

$x_0\cdot\sin\ \frac{2\pi}{T}t$

2.

A mass on the end of a spring is released from rest from an initial displacement A. Its oscillations have total energy E.

Later, the same mass is extended and released from a displacement of 2A. Which of the following gives the correct new time period and new total energy?

a)

Time period T; New energy 4E

b)

Time period T; New energy 2E

c)

Time period $\sqrt{2}T$ ; New energy 4E

d)

Time period $\sqrt{2}T$ ; New energy 2E

3.

The period of a particle undergoing SHM is T. The ratio: $\frac{acceleration\ of\ the\ particle}{displacement\ of\ the\ particle}$ is proportional to....

a)

$T^{-2}$

b)

$T^{-1}$

c)

$T$

d)

$T^2$

4.

A small point mass m is placed at the same distance from two identical fixed spherical masses far from any other masses. The point mass is released from rest. The point mass will....

a)

move upwards.

b)

stay where it is.

c)

move towards P and stop there.

d)

oscillate about point P.

5.

An object undergoes simple harmonic motion (SHM). The total energy of the object is proportional to....

a)

the amplitude of the oscillations.

b)

the time period of the oscillations.

c)

the frequency of the oscillations.

d)

the mass of the object.

6.

A beam of coherent light is incident on a single slit of width b. After passing through the slit, the light is incident on a screen at a distance D from the slit.

Which of the following changes, carried out separately, in respect of b and D will result in an increase in width of the first diffraction maximum formed on the screen?

a)

b decrease and D increase.

b)

b increase and D increase.

c)

b decrease and D decrease.

d)

b increase and D decrease.

7.

A parallel beam of monochromatic light of wavelength λ passes through a slit of width b. After passing through the slit the light is incident on a distant screen. The angular width of the central maximum is

a)

$2\ \frac{\lambda}{b}$ radians

b)

$\frac{\lambda}{b}$ radians

c)

$2\ \frac{\lambda}{b}$ degrees

d)

$\frac{\lambda}{b}$ degrees

8.

A single-slit diffraction experiment is performed using light of different colours. The width of the central peak in the diffraction pattern is measured for each colour. What is the order of the colours that corresponds to increasing widths of the central peak?

a)

red, green, blue

b)

red, blue, green

c)

blue, green, red

d)

green, blue, red

9.

In a double-slit interference experiment, the following intensity pattern is observed for light of wavelength λ. The distance between the slits is d. What can be deduced about the value of the ratio $\frac{\lambda}{d}$

a)

$\frac{\lambda}{d}$ is 100; the diffraction is non-negligible

b)

$\frac{\lambda}{d}$ is 0.01; the diffraction is non-negligible

c)

$\frac{\lambda}{d}$ is 100; the diffraction is negligible

d)

$\frac{\lambda}{d}$ is 0.01; the diffraction is negligible

10.

A transparent liquid forms a parallel-sided thin film in air.

Reflections from the top and bottom surfaces of the film result in three rays J, K and L. Which of the rays has undergone a phase change of π rad?

a)

J only

b)

J and L only

c)

J and K only

d)

J, K and L

11.

Monochromatic light of wavelength λ in air is incident normally on a thin film of refractive index n. The film is surrounded by air. The intensity of the reflected light is a minimum. What is a possible thickness of the film?

a)

$\frac{\lambda}{4n}$

b)

$\frac{3\lambda}{4n}$

c)

$\frac{\lambda}{n}$

d)

$\frac{5\lambda}{4n}$

12.

Monochromatic light is incident on two identical slits to produce an interference pattern on a screen. One slit is then covered so that no light emerges from it. What is the change to the pattern observed on the screen?

a)

Fewer maxima will be observed.

b)

The intensity of the central maximum will increase.

c)

The outer maxima will become narrower.

d)

The width of the central maximum will decrease.

13.

According to the Rayleigh criterion, when the diffraction patterns of two slits are just resolved....

a)

the first maximum of one diffraction pattern coincides with the central maximum of the other diffraction pattern.

b)

the central maximum of one diffraction pattern coincides with the central maximum of the other diffraction pattern.

c)

the first minimum of one diffraction pattern coincides with the central maximum of the other diffraction pattern.

d)

the first minimum of one diffraction pattern coincides with the first minimum of the other diffraction pattern.

14.

A coherent beam of light of wavelength λ is incident on a double slit.

There is a bright fringe at O and a bright fringe at P. Between O and P there are three dark fringes.

Which of the following is the path difference between the light from the two slits arriving at P?

a)

$1.5\lambda$

b)

$2\lambda$

c)

$3\lambda$

d)

$4\lambda$

15.

Two galaxies with an angular separation at the observer
$5.0\times10^{-4}$ radians are observed with a radio telescope. Both galaxies emit radio waves of wavelength $2.5\times10^{-2}$ m.
The images of the galaxies are just resolved by the telescope. The diameter of the circular collecting dish of the telescope is....

a)

61 m

b)

50 m

c)

30 m

d)

25 m

16.

A diffraction grating is used to observe light of wavelength 400 nm. The light illuminates 100 slits of the grating. What is the minimum wavelength difference that can be resolved when the second order of diffraction is viewed?

a)

1 nm

b)

2 nm

c)

4 nm

d)

8 nm

17.

An observer standing a short distance away from the object is able to hear the sound. Which of the following describes the sound the observer is able to hear?

a)

A sound of constant frequency but varying in amplitude

b)

A sound of constantly varying frequency

c)

A sound with a frequency of 50 Hz

d)

A sound with a frequency of 200 Hz

18.

A source of sound moves away from an observer. The observed frequency of the sound differs from the frequency emitted by the source because the....

a)

observed wavelength of the sound is less than the emitted wavelength.

b)

observed wavelength of the sound is greater than the emitted wavelength.

c)

speed of sound relative to the observer has decreased.

d)

speed of sound relative to the observer has increased.

19.

Two lines X and Y in the emission spectrum of hydrogen gas are measured by an observer stationary with respect to the gas sample.

The emission spectrum is then measured by an observer moving away from the gas sample.

What are the correct shifts X* and Y* for spectral lines X and Y?

a)

b)

c)

d)

20.

A train moving at speed u relative to the ground, sounds a whistle of constant frequency f as it moves towards a vertical cliff face. The sound from the whistle reaches the cliff face and is reflected back to the train. The speed of sound in stationary air is c.

What whistle frequency is observed on the train after the reflection?

a)

$\frac{\left(c+u\right)}{\left(c-u\right)}f$

b)

$\left(c+u\right)f$

c)

$\left(c-u\right)f$

d)

$\frac{\left(c-u\right)}{\left(c+u\right)}f$

Topic 9 IB Physics

Total questions: 20

Worksheet time: 20mins

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