Physics — 1999

The force between molecules of the same substance is termed

A net force of magnitude 0.6N acts on a body of mass 40g, initially at rest. Calculate the magnitude of tire resulting acceleration.

Palm oil from a bottle flows out more easily after it as been heated because the

A body weighing 100N moves with a speed of 5ms-1 in a horizontal circular path of radius 5m. Calculate the . magnitude of the centripetal force acting on the body. (g = 10ms-2)

A motorcyclist, passing a road junction, moves due west for 8 s at a uniform speed of 5ms -1 . He then moves due north for another 6 s with the same speed. At the end of the 6s his displacement from the road junction is 50m in the direction of

The time rate of change of displacement is known as

A stone of mass 0.7kg is projected vertically , upwards with a speed of 5ms -1 . Calculate the maximum height reached. (Take g as 10ms -2 and neglect air resistance)

If the force of attraction between the sun and the 1 planets is removed; the planets will

A 15kg mass, suspended from a ceiling, is pulled aside with a horizontal force, F, as shown in the diagram above. Calculate the value of the tension, T. (g = 10ms -2 )

A pendulum bob executing simple harmonic motion has 2cm and 12Hz as amplitude and frequency respectively. Calculate the period of the motion.

A trolley of mass 4kg moving on a smooth horizontal platform with a speed of 1.0ms -1 collides perfectly with a stationary trolley of the same mass on the same platform. Calculate the total momentum of the two trolleys immediately after the collision.

The ice point of an ungraduated mercury-in-glass thermometer is X, while its steam point is 90 o . This thermometer reads 60 o when the true temperature is 40 o C Calculate the value of X.

Iron at 30 o C feels colder to the hand than wood at 28 o C because

An iron rod of length 50m and at a temperature of 60 o C is heated to 70 o C. Calculate its new length. (Linear expansivity of iron = 1.2 x 10 -5 K -1 )

The heat capacity of a substance is the energy

The temperature of a piece of metal of mass 9 g is raised from 10 o C to 110 o C when it absorbs 108J of heat energy. Determine the specific heat capacity of the metal in J kg -1 K -1

Which of the following statements is not correct?

Calculate the heat energy required to change 0.1kg of ice at 0 o C to water boiling at 100 o C. (Specific heat capacity of water = 4200 J kg -1 K -1 ) (Specific latent heat of fusion of ice = 336,000 J kg -1 )

Which of the following statements about evaporation is not correct?

Calculate the power rating of an immersion heater used for 10 minutes to increase the temperature of 10kg of water by 15K. (Specific heat capacity of water = 4200 J l -1K -1 )

A ray of light is incident on 'a plane mirror at an angle of 20o. This mirror is rotated through, twice this angle, In this new position the angle between the incident ray and the reflected ray is

The air column in a resonance tube is set into resonance by a vibrating tuning fork. The resultant waves in the air column will be

The image of an object is located 6cm behind a convex mirror. If its magnification is 0.6, calculate the focal length of the mirror

The refractive index of glass for yellow light is greater than that for red light because yellow light

The real image of an object formed by a converging lens of focal length 15cm, is three times the size of the object. Calculate the object distance

Which of the following statements is not correct about long sight?

The amplitude of a wave is the

ln order to obtain a sound note of a high pitch from a wire stretched by a constant tension, the wire must be

If the position of resonance in a resonance tube is 16.50cm from open end of the tube, calculate the distance from the open end to the next position where resonance occurs. (Neglect end-correction)

Thunder is usually heard some seconds after lightning is observed because

Using the data on the diagram above, calculate the potential difference across the 20- Ω resistor. (Neglect the internal resistance of the cell)

Using the diagram above, calculate the effective capacitance of the circuit

The parts of a bar magnet at which the magnetic effect is strongest are called the

A resistance wire of length 2 m and of uniform cross-sectional area 5.0 x 10 -7 m 2 has a resistance of 2.2 Ω Calculate its resistivity

Magnetic flux density is defined as the

The voltage and current in the primary of a transformer are 200V and 2Arespectively. lf the transformer is used to light ten 12 V, 30 W bulbs, calculate its efficiency.

In a uniform electric field, the magnitude of the force on a charge of 0.2 C is 4N. Calculate the electric field intensity

A 10 Ω coil takes 21 s to melt 10g of ice at 0ºC. Assuming no heat losses, determine the current in the coil. (Specific latent heat of fusion of ice = 336 Jg\(^{-1}\))

A point charge of magnitude 2μC is moved through a distance of 0.02 m against uniform field of intensity 25 Vm -1 Calculate the work done on the charge

Bohr’s atomic model proves most successful for the explanation of the. I. structure of the hydrogen atom; II. line spectra of the hydrogen atom; III. Multi-electron atoms. Which of the statements above is/are correct?

The diagram above illustrates the energy transitions of five electrons of an atom. Which of the transitions will produce the emission of longest wavelength?

Which of the transitions will produce the emission of highest frequency?

I. All elements emit and absorb characteristic spectra. II. Spectral analysis is an important method of identifying environmental pollutants. III. The chemical composition of stars could be determined using spectral analysis. Which of the statements above are correct?

A metal has work function of 4.375 eV Calculate its threshold frequency. (h = 6.6 x 10 -34 Js; 1eV = 1.6 x 10 -19 J)

The half-life of a radioactive substance is

The half-life of a radioactive element is 5 Calculate its decay constant

A sheet of paper is placed in the path of the following radiations: I. Alpha particles II. Beta particles III. Gamma rays. Which of the radiations will pass through the sheet of paper?

Which of the following are the essential parts of an atomic bomb?

Which of the following is not a safety precaution in a nuclear station?