A catapult used to hold a stone of mass 500g is extended by 20cm with an applied force F. If the stone leaves with a velocity of 40m/s, the value of F is
- A. 4.0 x 102N
- B. 2.0 x 103N
- C. 4.0 x 103N
- D. 4.0 x 104N
If the force and the velocity on a system are each reduced simultaneously by half, the power of the system is
- A. doubled
- B. reduced to a quarter
- C. reduced by half
- D. constant
At a fixed point below a liquid surface, the pressure downwards is P1 and pressure upwards is P2. It can be deduced that?
- A. P1 > P2
- B. P1 ā„ P2
- C. P1 < P2
- D. P1 = P2
The velocity ratio of a machine is 5 and its efficiency is 75%. What effort would be needed to lift a load of 150N with the machine?
- A. 20N
- B. 30N
- C. 40N
- D. 50N
I. Its velocity is constant
II. No work is done on the body
III. It has constant acceleration directed away from the centre
IV. The centripetal force is directed towards the centre
Which combination of the above is true of a body moving with constant speed in a circular track?
- A. II and IV
- B. I and IV
- C. II and III
- D. I and III
When a ship sails from salt water into fresh water, the fraction of its volume above the water surface will
- A. increase
- B. decrease
- C. remain the same
- D. increase then decrease
if āx is the uncertainty in the measurement of the position of a particle along the x-axis and āPx is the uncertainty in the measurement of the linear momentum along the x-axis, then the uncertainty principle relation is given as
- A. āx āPx ā„ h
- B. āx āPx = 0
- C. āx āPx < h
- D. āx āPx = ā
A semiconductor diode is used in rectifying alternating current into direct current mainly because it
- A. allows current to flow in either direction
- B. is non-linear
- C. offers a high input resistance
- D. allows current to flow only in one direction
2311Na + Proton ā pqX + alpha particle
What are the values of p and q respectively in the equation above?
- A. 10 and 20
- B. 12 and 24
- C. 20 and 10
- D. 24 and 12
In the Rutherford scattering experiment, a beam of alpha particles was fired at a thin gold film with some of the particles being considerably deflected. This shows that
- A. a gold nucleus contains protons, neutrons and electrons uniformly distributed in a tiny volume
- B. the gold nucleus is positively charged and is concentrated in a tiny volume
- C. the gold nucleus emitted alpha particles
- D. the gold nucleus is concentrated in a tiny volume and contains alpha particles
in a series R-L-C circuit at resonance, the voltages across the resistor and the inductor are 30V and 40V respectively, what is the voltage across the capacitor?
- A. 30V
- B. 40V
- C. 50V
- D. 70V
What is the speed of a particle of mass 10-27kg whose wavelength is 10-8m.
[h = 6.63 x 10-34Js]
- A. 6.63ms-1
- B. 66.30ms-1
- C. 663.00ms-1
- D. 6630.00ms-1
Gamma rays are produced when
- A. high velocity electrons are abruptly stopped in metals
- B. energy changes occur within the nucleus of atoms
- C. energy changes occur within the electronic structure of atoms
- D. electrons are deflected in very strong magnetic fields
The core of an efficient transformer should consist of laminated pieces of metal in order to
- A. increase the heat produced by increasing the eddy current
- B. increase the heat produced by reducing the eddy current
- C. reduce the heat produced by increasing the eddy current
- D. reduce the heat produced by reducing the eddy current
At what frequency would a 10H inductor have a reactance of 2000ā¦?
- A. Ļ/200Hz
- B. Ļ/100Hz
- C. 100/ĻHz
- D. 100ĻHz
In fleming’s right-hand rule, the thumb, the forefinger and the middle finger if held mutually at right angles represent respectively, the
- A. motion, the field and the induced current
- B. induced current, the motion and the field
- C. field, the induced current and the motion
- D. induced current, the field and the motion
A galvanometer has a resistance of 5Ī©. By using a shunt wire of resistance 0.05Ī©, the galvanometer could be converted to an ammeter capable of reading 2Amp. What is the current through the galvanometer?
- A. 2mA
- B. 10mA
- C. 20mA
- D. 25mA
A 3000W electric cooker is to be used on a 200V mains circuit. Which of the fuses below can be used safely with the cooker?
- A. 2A
- B. 5A
- C. 10A
- D. 20A
Four cells each of e.m.f 1.5V and internal resistance of 4Ī© are connected in parallel. What is the effective e.m.f. and internal resistance of the combination?
- A. 6.0V, 16Ī©
- B. 6.0V, 1Ī©
- C. 1.5V, 4Ī©
- D. 1.5V, 1Ī©
Steel is more suitable for permanent magnet than iron because the former
- A. is easily demagnetized by shaing vigorously
- B. is an alloy of many metals
- C. is easily magnetized by alternating current through one cycle
- D. retains magnetism more than iron
Which of the following electromagnetic waves is least energetic?
- A. Infra-red rays
- B. X-rays
- C. Ultra-violet rays
- D. Gamma rays