A quantity of water at 0 °C is heated to 30 °C. For each degree rise in temperature, its density will———
- A. rise steadily
- B. fall steadily
- C. fall and then rises
- D. rise and then falls
The engine of a car provides a forward force of 1240 N and the total resistive force on the car is 800N. If the mass of the car is 1220 kg, determine the distance the car has to travel from the rest before acquiring a speed of 4 m s\(^{-1}\).
- A. 44.0 m
- B. 22.2 m
- C. 11.1 m
- D. 5.5 m
Which of the folowing statements about light travelling from one material medium to another is not correct?
- A. The refracted angle is less than the incident angle if the speed is higher in the first material
- B. Its wavelength does not change
- C. It bends away from the normal if the speed is lower in the first material
- D. Its frequency changes.
Which of the following concepts is a method of heat transfer that does not require a material medium?
- A. Conduction
- B. Diffusion
- C. Convection
- D. Radiation
The diameter of a brass ring at 30 °C is 50.0 cm. To what temperature must this ring be heated to increase its diameter to 50.29 cm? [ linear expansivity of brass = 1.9 x 10\(^{-5}\) K\(^{-1}\)]
- A. 152.6 °C
- B. 182.6 °C
- C. 306.1 °C
- D. 335.3 °C
Which of the following statements-about electromagnetic waves is not correct?
- A. They carry energy as they travel through space
- B. They travel with the speed of light
- C. They are longitudinal
- D. The electric and magnetic fields are at right angles to each other
The distance between the fixed points of a mercury-in-glass thermometer is 30 cm. Determine the temperature when the mercury level is 10.5 cm above the lower fixed point
- A. 28.6ºC
- B. 30.0 ºC
- C. 35.0 ºC
- D. 40.5 ºC
A hunter fires a gun at a point 408 m away from a cliff. If he hears an echo 2.4 s later, determine the speed of the sound wave
- A. 340 ms\(^{-1}\)
- B. 380 m s\(^{-1}\)
- C. 400 m s \(^{-1}\)
- D. 680 m s\(^{-1}\)
When the direction of vibration of the particles of a medium is perpendicular to the direction of propagation of a wave, the wave is said to be——–
- A. longitudinal
- B. transverse
- C. mechanical
- D. a sound wave
The half-life of a radioactive substance is 15 hours. If at some instance, the sample has a mass of 512 g, calculate the time it will take \(\frac{7}{8}\) of the sample to decay
- A. 15 hours
- B. 30 hours
- C. 45 hours
- D. 60 hours
Gamma rays are produced when?
- A. high velocity electrons are abruptly stopped in metals
- B. energy changes occur within the nuclei of atoms
- C. energy changes occur within the electronic structure of atoms
- D. electrons are deflected in very strong magnetic fields
If the kinetic energy of an electron is 100 eV, what is the wavelength of the de-Broglie wave associated with it? [h = 6.6 x 10\(^{-34}\) J s, e = 1.6 x 10\(^{19}\)C, m\(_{e}\), = 9.1 x 10\(^{-31}\) kg]
- A. 1.22 x 10\(^{-10}\)m
- B. 4.10 x 10\(^{-10}\)m
- C. 3.90 x 10\(^{-10}\)m
- D. 5.50 x 10\(^{-14}\)m
Arrange the following radiations in order of increasing ionization of air.
I. Alpha
Il. Gamma
IIl. Beta
- A. I < III < II
- B. II < I < III
- C. II < III < I
- D. I < II
In doping an intrinsic semiconductor to produce a p-type semiconductor,
- A. the semiconductor is heated up
- B. a donor element is added
- C. an acceptor element is added
- D. the semiconductor is conducted to a battery
One major reason why electrical appliances in homes are normally earthed is that the———–
- A. person touching the appliance is safe from electric shock
- B. appliances are maintained at a higher p.d. than the earth
- C. appliances are maintained at a lower p.d. than the earth
- D. appliances are maintained at the same p.d. with that of the earth
A lamp is rated 240 V, 60 W. Determine the resistance of the lamp when lit?
- A. 120\(\Omega\)
- B. 240\(\Omega\)
- C. 540\(\Omega\)
- D. 960\(\Omega\)
In a series R-L-C circuit at resonance, impedance is—-
- A. maximum
- B. minimum
- C. capacitive
- D. inductive
The speed of fast-moving neutrons in a nuclear reactor can be reduced by using?
- A. graphite rods
- B. concrete shield
- C. iron rods
- D. boron rods
.An inductor of inductance 10 H is connected across an a.c circuit source of 50 V, 100 Hz. What is the current in the circuit? [\(\pi\) = 3.14]
- A. 0.200A
- B. 0.070A
- C. 0.050A
- D. 0.008A
A galvanometer with a full-scale deflection of 20 mA is Converted to read 8 K by connecting a 395 \(\Omega\) resistor in series with it. Determine the internal resistance of the galvanometer
- A. 2.5\(\Omega\)
- B. 5.0\(\Omega\)
- C. 8.0\(\Omega\)
- D. 10.0\(\Omega\)
Which of the following statements about electric potential energy is not correct?
- A. The electric potential energy of a positively charged particle increases when it moves to a point of higher potential
- B. The electric potential energy of a negatively charged particle increases when it moves to a point of lower potential
- C. The electric potential energy of a positively charged particle decreases when it moves to a point of higher potential
- D. The work done in taking a charged particle around a closed path in an electric field is zero.