Name:Class: Date:SMK (L) Methodist Kuala LumpurSTPM Physics Semester 2Revision3 (Percubaan STPM 2009 Johor)

1Three point charges -1 C, +2 C and +3 C are placed on a straight line respectively as shown in the figure below.

The resultant force acting on S due to R and T isA11 N towards TC15 N towards R

B15 N towards TD105 N towards R

2The figure below shows a positive plate and a negative plate which are parallel. One electron is released near the negative plate.

Which of the following is true concerning the force F acting on the electron and the kinetic energy Ek of the electron along its motion from the negative plate to the positive plate?FEk

AIncreaseIncrease

BIncreaseConstant

CConstantConstant

DConstantIncrease

3Two identical metal solid spheres X and Y which are charged positively with Q1 and Q2 (Q1>Q2) respectively. Which of the following statements is true concerning sphere X and sphere Y?AThe electric field intensities on the surface of sphere X and sphere Y are zero.

BThe electric field intensities inside sphere X and sphere Y are zero.

CThe electric field intensity inside sphere X is more than the electric field intensity inside sphere Y.

DThe electric potentials inside sphere X and sphere Y are zero.

4Which of the following statements concerning an isolated charge conductor which is stationary and non-uniform in shape is not true?AThe surface charge density of the conductor is uniform.

BThe charge of the conductor only resides on the surface of the conductor.

CThere is no electric field inside the conductor.

DThere is no magnetic field surrounding the conductor.

5

A 100 F capacitor is charged and later the charge acquire is discharged through a 10 k resistor. What is the value of the ratio?A2BIn 2C1 In 2D

6

When potential difference V is applied across the ends of a copper wire which has a diameter d and length l, the drift velocity of electrons in the wire is v. What is the drift velocity of the electrons, in terms of v, in a copper wire which has diameter and length, and is applied with potential difference 2V across its ends?AvB2vC4vD8v

7If the order of magnitudes for current density and number of free electrons per unit volume in a metal are 106 A m-2 and 1028 m-3 respectively, what is the order of magnitude for the drift velocity of free electrons in the metal?A104 m s-1B102 m s-1C10-2 m s-1D10-4 m s-1

8In the circuit as shown in the figure below, the resistance of the voltmeter is 500 .

What is the reading of the voltmeter?A0.75 B1.00 C1.25 D3.00

9In a circuit as shown in the figure below, cell E1 has e.m.f. of 2.0 V and internal resistance which can be neglected. The length of the potentiometer wire AB is 100 cm and when switch S is opened, the balance length AX is 75 cm. When switch S is closed, length AX is 60 cm.

What is the internal resistance of cell E2?A2.5 VB3.3 VC5.0 VD6.0 V

10An electron moves in a straight line in vacuum where there is a magnetic field and an electric field acting perpendicular to each other. If the electric field is removed, the electron will move withAsame speed in a circle.

Bsame speed in a parabola.

Csame speed in a straight line.

Da lower speed in a circle.

11The magnetic field of Earth at the centre of a conductor circular coil of radius 5.0 cm is T. The direction of the Earths magnetic field is perpendicular to the plane of the coil. The magnetic field is cancelled by the magnetic field produced at the centre of the coil when a current flows in the coil. What is the magnetic field of the current flow?A0.9 AB1.4 AC1.8 AD5.6 A

12When a constant current flows in a moving coil galvanometer, the coil will be deflected by a constant torque becauseAthe coil is wound round a soft iron core.

Bthe coil undergoes critical damping.

Cthe coil is placed in a radial magnetic field.

Dthe coil is controlled by a helical spring.

13

The magnetic flux density in a solenoid which has 400 turns and uniform cross-sectional area is T when the solenoid carries a current of 2 A. If the magnetic flux density of the solenoid is assumed uniform, what is the self-inductance of the solenoid?A0.5 HB1.0 HC2.0 HD2.5 H

14A sinusoidal a.c. source with period T is connected to a pure capacitor. Which of the following graphs best represents the variation of energy per unit time, P, stored in the capacitor with time t in a complete oscillation?

15(a) What is a multiplier? [1 mark](b) State the function of a multiplier.[1 mark]

(c) A galvanometer of resistance 30 has a full-scale deflection of 20 mA. It is to be converted into a voltmeter of range 0 3.0 V.Describe briefly, with the aid of a circuit diagram to show how a multiplier is connected to the galvanometer and calculate the resistance of the multiplier required? [3 marks]

16(This question is based on an experiment conducted by NASA on a novel source of energy for a space shuttle)Above the equator of the Earth, the Earths magnetic field runs horizontally in the south-north direction. A space-shuttle flying from west to eat above the equator cuts perpendicularly across the magnetic field as shown in the diagram below. A small satellite is attached to the shuttle by a very long thin copper cable. It is proposed to use the e.m.f. generated in the cable as a source of electrical energy for the shuttle.

(a) Explain how is there an e.m.f. generated in the cable? [1 mark](b) Calculate the magnitude of this e.m.f. using the following data: Cable length = 20 km Speed of shuttle and satellite = 7.0 km s-1

Horizontal component of the Earths magnetic flux density = T. [3 marks](c) State the direction of the generated e.m.f. [1 mark]

17(a) A stationary negatively-charged particle experiences a force in the direction of the field in which it is placed. State and explain, whether the field is magnetic, electric or gravitational. [2 marks](b) Calculate the magnitude if the electric field strength required to maintain an electron in a fixed position in the gravitational field of the Earth, at its surface. [2 marks]

(Take g = 9.81 m s-2; mass of electron = kg)(c) Neon-20 atoms are ionized by the removal of one electron from each atom. For a Neon-20 ion, i. state the charge on the ion, [1 mark] ii. calculate its mass. [2 marks](d) The neon ions in (c) are accelerated from rest in vacuum through a potential difference of 1400 V. They are then injected into a region of space where there are uniform electric and magnetic fields acting at right angles to the incident direction of motion of the ions as shown in the following diagram. The electric field strength E and the flux density of the magnetic field is B.

i. Draw and indicate clearly the directions of the electric field and magnetic fields so that the ions pass through undeflected through the region. [2 marks] ii. Calculate the speed of the accelerated ions on entry into the region of the electric and magnetic fields. [2 marks]

iii. The electric field strength E is V m-1. Calculate the magnitude of the magnetic flux density so that the ions are not deflected in the region of the fields. [2 marks](e) The mechanism by which the neon atoms in (c) are ionized is changed so that each atom loses two electrons. State and explain what change occurs in: i. the speed of the ions entering the region of the electric and magnetic fields as in (s) above. [1 mark] ii. the path of the ions in the region of the electric and magnetic fields. [1 mark]

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