# Question 1

MULTIPLE-CHOICE QUESTIONS

Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A–D) next to the question number (1.1–1.10) in the ANSWER BOOK, for example 1.11 E.

1.1 Two forces, F1 and F2, are applied on a crate lying on a frictionless, horizontal
surface, as shown in the diagram below.

The magnitude of force F1 is greater than that of force F2.

The crate will …

A. accelerate towards the east.
B. accelerate towards the west.
C. move at a constant speed towards the east.
D. move at a constant speed towards the west. (2)

1.2 A person stands on a bathroom scale that is calibrated in newton, in a stationary elevator. The reading on the bathroom scale is W.

The elevator now moves with a constant upward acceleration of ¼g, where g is the gravitational acceleration.

What will the reading on the bathroom scale be now?

A. ¼w
B. ¾w
C. w
D. 5⁄4w (2)

1.3 Which ONE of the graphs below correctly represents the relationship between the kinetic energy (K) of a free-falling object and its speed (v)?

1.4 The simplified diagram below shows a rocket that has been fired horizontally, accelerating to the west.

Which ONE of the statements below best explains why the rocket accelerates?

A. The speed of the exhaust gases is smaller than the speed of the rocket.
B. The pressure of the atmosphere at the back of the rocket is less than at the front.
C. The air outside the rocket exerts a greater force on the back of the rocket than at the front.
D. The rocket pushes the exhaust gases to the east and the exhaust gases push the rocket to the west. (2)

1.5 The graph below represents the relationship between the work done on an object and the time taken for this work to be done.

The gradient of the graph represents the …

A. power.
B. momentum.
C. kinetic energy.
D. potential energy. (2)

1.6 A line emission spectrum is formed when an excited atom moves from a …

A. higher to a lower energy level and releases energy.
B. higher to a lower energy level and absorbs energy.
C. lower to a higher energy level and releases energy.
D. lower to a higher energy level and absorbs energy. (2)

1.7 Two charged spheres of magnitudes 2Q and Q respectively are placed a distance r apart on insulating stands.

If the sphere of charge Q experiences a force F to the east, then the sphere of charge 2Q will experience a force …

A. F to the west.
B. F to the east
C. 2F to the west
D. 2F to the east (2)

1.8 The four resistors P, Q, R and T in the circuit below are identical. The cell has an emf ε and negligible internal resistance. The switch is initially CLOSED.

Switch S is now OPENED. Which ONE of the following combinations of
changes will occur in P, R and T?

1.9 A DC current passes through a rectangular wire loop OPQR placed between two pole pieces of a magnet, as shown below.

Which TWO segments of the loop will experience an electromagnetic force when the loop is in the position above?

A. OP and PQ
B. QR and RO
C. OP and QR
D. RO and OP (2)

1.10 When light of a certain wavelength is incident on a metal surface, no electrons are ejected. Which ONE of the following changes may result in electrons being ejected from the metal surface?

A. Increase the intensity of the light.
B. Use light with a much shorter wavelength.
C. Use metal with a larger work function.
D. Increase the surface area of the metal. (2)