1. A train is traveling at 30ms^−1 towards a stationary observer. It sounds a horn of frequency $450Hz$.

Which of the following statements is true about the observed frequency compared with the emitted frequency as the train approaches?

2. A thin beam of monochromatic blue light is incident upon a single slit barrier. The emerging light then passes through a double slit arrangement and falls on a screen some distance away.

An interference pattern is observed on the screen. In order to increase the distance between adjacent fringes, which of the following actions would be appropriate?

3. For an open pipe, the frequency of the first harmonic is $f$ and its wavelength is $\lambda$.

For a given harmonic of the same pipe, the ranges of motion of the particles in the pipe are shown below.

Three statements about the standing wave shown in this pipe are

I. The frequency is
II. The wavelength is λ/4
III. The wavelength is less than λ

Which statements are true?

4. A string fixed at both ends oscillates in a standing wave as shown with a wavelength of $400mm$.

What is the length of the string?

5. A particle undergoes simple harmonic motion. Which of the following can be an expression of acceleration $a$ in terms of displacement $x$ and a constant value k?

6. The graph shows the variation with time $t$ of the displacement $s$ of an object suspended by a spring. At what time is the acceleration in the negative direction at a maximum??

7. A radio wave of frequency $90MHz$ travels a distance $d$. The number of wavelengths that can fit into this distance is 6000. What is $d$?

8. A traveling source produces sound waves nearby a child. The wavefronts of the sound waves and the position of a child are seen in the figure below.

The frequency of the generated sound waves is $f$. Which of the following is correct for both the direction of motion of the source and the observed frequency of the sound waves by the child?

9. A simple pendulum executing simple harmonic motion is released from one end and reaches equilibrium position in $2s$. Just after the equilibrium position, the length of the pendulum is reduced to one-fourth of its initial value because of wrapping around a nail.

What is the period of the simple pendulum?

10. A mass-spring system rests on a frictionless surface. The mass is pulled to the right and released from a point $X$ at $t=0s$.

The mass executes simple harmonic motion between the points $X$ and $Y$. The mass reaches point Y for the first time at t=6s. Which of the following correctly shows directions of velocity and acceleration of the mass at t=10s?

11. A mass-spring system executes simple harmonic motion with a period $T$ in a vertical plane. What is the period when the oscillating mass is doubled and the system is brought to a planet where the gravitational field strength at the surface is halved?

12. For a body executing simple harmonic motion, which statement is not possible?

13. For a wave traveling in a medium, the variation of the particles' displacement with distance travelled is shown in the following graphs, which represent the wave at different moments in time of a wave travelling to the right.

Graph I shows the wave at t=0 s, while graph II is at t=1s.

The time difference between the two graphs is less than the wave's period.

Graph I

Graph II

What is the wave speed?

14. The diagram shows a beam of light passing from medium $X$ to medium $Y$.

If the angle of incidence of the light increases, which of the following changes can be implemented to keep the angle of refraction the same?

15. A radio with a bright light is placed outside the doorway of long, dark room as shown. A student in a corner near the door can hear the sound of the radio while standing in the dark region of the room.

Which property of waves correctly explains why light does not reach her while the sound does?

16. A boy tied two identical ropes to a fixed wall for a fitness exercise. He shakes the ropes to form waves.

A point on the right rope oscillates with a period of $0.4s$. A point on the left rope oscillates with a period of $0.2s$.

What is the ratio = [wavelength of right rope]/[wavelength of left rope]?

17. A simple pendulum undergoes simple harmonic motion. The graph shows the variation of a quantity $y$ with horizontal displacement $x$ from the equilibrium position.

Which of the following quantities could be represented by quantity $y$?

18. A taut string on a guitar is fixed at both ends.

What is [wavelength of fourth harmonic]/[wavelength of second harmonic] for the string?

19. A light source approaches a stationary receiver at an increasing speed. The frequency of the emitted light is constant. Which graph shows how the observed frequency $f$ by receiver varies with the speed v of the light source?

A.			B.
C.			D.

20. A fire truck’s siren emits a frequency of f0. Starting from rest, it moves with constant acceleration and passes a stationary observer at t=to. Which graph shows the variation of observed frequency f by the stationary observer with time?

A.			B.
C.			D.

21. A student blows across the open end of a narrow cylinder which is closed at the other end. If the length of the cylinder is $15.0cm$ and the speed of sound is 340 ms^−1, What is the frequency of the wave at the third harmonic?

22. Two identical objects $P$ and $Q$ are connected to identical springs. Both P and $Q$ are performing simple harmonic motion (SHM) around equilibrium level $O$.

The diagram shows positions of $P$ and $Q$ at time $t=0$. Which graph shows how kinetic energy of $P$ and Q vary with time t?

A.				B.
C.				D.

23.  

Two sources $A$ and $B$ produce waves of amplitude $a$, and period T on the surface of a swimming pool as shown. The wave generator $A$ is turned on at time $t=0$, and $B$ at time t=T/2. Both generators create a crest when first turned on. The wavefronts shown in the illustration are one wavelength apart each. Determine the amplitude of the oscillation of the medium at point $C$.

25. A geostationary satellite is used for TV broadcasting. It orbits so that its position remains fixed above a receiver on earth. It undergoes circular motion with a speed of $v$ and the emitted frequency for a channel is f. Which of the following is correct?