Physics — 2008

If the air inside a rigid box is heated, the i, average speed of the molecules increases ii. pressure of the air increases iii. average separation of the molecule increases. Which of the statements above are correct?

Which of the following sets of quantities is fundamental?

which of the following statements about Archimedes' principle is correct? The upthrust on a body is a measure of the

Which of the following is/are in random motion? i. Pollen grains in water ii. The molecules of hydrogen gas ii. Fine chalk particles floating in air

A car travelling with a uniform velocity of 30ms -1 along a horizontal road overcomes a constant frictional force of 600N. Calculate the power of the engine of the car

A rectangular block of dimensions 2.0m x 1.0m x 0.5m weighs 200N. calculate the maximum pressure exerted by the block on a horizontal floor.

A very sensitive spring balance was used to determine the weight of an object at the north pole. When the same spring balance was used to measure the weight of the same object at the equator, it was found to reduce. The explanation for this observation is that

The diagram above illustrates a Hare's apparatus. \(\mathit{e}_1, \mathit{e}_2\) represent densities and \(\mathit{h}_1, \mathit{h}_2\) heights of columns of liquids. Which of the following equations is correct?

The diagram above represents the displacement-time graph of the motion of an object thrown upwards. The velocity of the object at the point P is

The diagram above illustrates a bar magnet near a coil connected to a galvanometer, When the magnet is rapidly moves towards the coil i. e.m.f. is induced in the coil ii. the galvanometer needle deflects iii. the magnet is attracted by the coil. Which of the statements above is/are correct?

The mass attached to a string is moving in a circular path. If the speed is doubled, the tension in the string will be

An object of mass 2kg moving with a velocity 3ms -1 1 collides head-on with another object of mass 1kg moving in the opposite direction with a velocity of 4ms -1 . If the objects stick together after collision, calculate their common speed.

A ball is dropped and it hits the floor at a point A. It rebounds upward to a point B. While moving from A to B its?

Which of the following devices convert heat energy to electrical energy?

An object of mass 0.25kg moves at a height h above the ground with a speed of 4ms-1, if its mechanical energy at this height is 12 J, determine the value of h. [g = 10ms-1]

Which of the following equations for the efficiency of a machine is correct?

The design of the thermostat of an electric iron is based on the

A metal rod of length 50cm is heated from 40 o C to 80 o C. If the linear expansivity of the material is \(\alpha\), calculate the increase in length of the rod (in metres) in terms of \(\alpha\)

The cubic expansivity of a certain gas at constant pressure is \(\frac{1}{273} k^{-1}\). If a given mass of the gas is held at constant pressure and its volume at 0 o C is 273m 3 , determine the volume of the gas at 273 o C.

Water of mass 1.5kg is heated from from 30 o C to 80 o C using an electric kettle which is rated 5A, 230V. Calculate the time taken to reach the final destination [specific heat capacity of water 4200Jkg -1 K -1 ]

The working principle of a pressure cooker is based on the

It takes a shorter time for a liquid to boil at the top of a mountain than at the base because at the top, the

Light is considered as a transverse wave because it travels

In the day time, it is possible to see under shady areas such as under a tree because light has undergone

The distance between a concave mirror and an object placed in front of it is 1.0m. If the raduis of curvature of the mirror is 4.0m, the image formed will be

The image of an object formed by a convex mirror is

When viewed straight down, a fish in a pond is

A converging lens and a screen are placed 20 cm and 80 cm respectively from an object in a straight line so that a sharp image of the object is formed on the screen. If the object is 3cm high. Calculate the height of the image formed

Which of the following defects of vision is as a result of the eye ball being too long?

a sound wave is produced fron a source ans an echo is heard t seconds afterwards. If d is the distance of the reflecting surface from the source, v the speed, p the wavelength and T the period of the wave, then

A negatively charged rod is held close to an uncharged metal ball on an insulating stand. The ball will

Two bodies each carrying a charge of 2.00 x 10-10C are 5cm apart. Calculate the magnitude of the force between the charges.[\(\frac{1}{4\pi \mathit{E}_o} = 9.00 \times 10^9 Nm^2C{-2}\)]

If the charge on an object is measured as 4.0 x 10 -18 C, how many excess electrons does the object possess, given that the charge of an electron is 1.6 x 10 -18 C

Which of the following is a unit of the time rate of flow of electric charges?

A wire 1.0m long and with cross-sectional area 2.0 x 10-7 m2 has a resistance of 0.1\(\Omega\). Calculate the electrical conductivity of the wire

Three capacitors each of capacitance 1.5\(\mu F\) are connected in series. The total capacitance in the circuit is

A voltmeter is a device that

Which of the following actions will not increase the sensitivity of a moving coil galvanometer?

Fleming's right hand rule is also called the

A transformer is required to supply 12 V rms to operate a toy train set from a 240 V rms . If the number of turns in the in the secondary coil is 100, calculate the number of turns required in the primary coil

A direct current of 5A flow through a 0.2H inductor. Calculate the energy stored in the inductor

Both \(\gamma\)-rays and X-rays i. can be produced by thermionic emission ii. have low frequencies iii. have short wavelengths. Which of the statements above is/are correct?

When a radioactive substance undergoes a beta decay, its

Nuclear fission is preffered to nuclear fusion in the generation of energy because

Control in nuclear reactors is effected with boron rods because rhe rods have the ability to

A radioactive element has a decay constant of 0.077s -1 . Calculate its half-life

The diagram above shoes three forces F 1 , F 2 and F 3 , which of the following ewuations is correct?