PHYSICS JAMB CBT

I. The earth is not spherical but elliptical in shape.
II. Variation in latitude and longitude.
III. Rotation of the earth on its axis.
IV. Variation in the density of the earth.

On which combination of the above does the weight of an object vary on the earth’s surface?

If a spherical metal bob of radius 3cm is fully immersed in a cylinder containing water and the water level rises by 1cm, what is the radius of the cylinder?

The efficiency of a machine is always less than 100% because the

The height at which the atmosphere ceases to exist is about 80km. If the atmospheric pressure on the ground level is 760mmHg, the pressure at a height of 20km above the ground level is

Which of the following consists entirely vector quantities?

The diagram below is a block-and-tackle pulley system in which an effort of 80N is used to lift a load of 240N. The efficiency of the machine is

A stone of mass 1kg is dropped from a height of 10m above the ground and falls freely under gravity. Its kinetic energy 5m above the ground is then equal to

In the diagram above, which of the simple pendula will resonate with P when set into oscillation?

The terrestrial telescope has one extra lens more than the astronomical telescope. The extra lens is for

A string is fastened tightly between two walls 24cm apart. The wavelength of the second overtone is

The thermometric substance of an absolute thermometer is

Ice cubes are added to a glass of warm water. The glass and water are cooled by

A working electric motor takes a current of 1.5A when the p.d. across it is 250V. If its efficiency is 80%, the power output is

In a Daniel Cell, the depolarizer, positive and negative electrodes are respectively

The cost of running five 6W lamps and four 100W lamps for 20 hours if electrical energy costs N10.00 per KWh is

When a piece of rectangular glass block is inserted between two parallel plate capacitors, at constant plate area and distance of separation, the capacitance of the capacitor will

The process of energy production in the sun is

I. Low pressure.
II. High pressure.
III. High p.d.
IV. Low p.d.

Which combination of the above is true of the conduction of electricity through gases?

A transistor functions mainly as a

Which of the following metals will provide the greatest shield against ionizing radiation?

Energy losses through eddy currents are reduced by using

The magnetic force on a charged particle moving with velocity v is

The force on a current carrying conductor in a magnetic field is greatest when the

The primary coil of a transformer has N turns and is connected to a 120V a.c. power line. If the secondary coil has 1000 turns and a terminal voltage of 1200 volts, what is the value of N?

A copper cube weights 0.25 N in air, o.17N when completely immersed in paraffin oil and o.15N when completely immersed in water. The ratio of upthrust in oil to upthrust in water is

A wheel and axle is used to raise a load of 500 N by the application of an effort of 250N. If the radii of the wheel and the axle are 0.4cm and o.1cm respectively, the efficiency of the machine is

If the distance between two suspended masses 10kg each is tripled, the gravitational force of attraction between them is reduced by

If the total force acting on a particle is zero, the linear momentum will

the effect of a particle in a fluid attaining its terminal velocity is that the

A coin placed below a rectangular glass block of thickness 9cm and refractive index 1.5 is viewed vertically above the  Joint Admissions and Matriculation Board block. The apparent displacement of the coin is

The radiator of a motor car is cooled by

I. Temperature.
II. Density of air molecules.
III. Pressure.
IV. Pitch.

Which of the above will affect the velocity of sound in air?

Which of the following is a characteristic of stationary wave?

To produce an enlarged and erect image with a concave mirror, the object must be positioned

The property that is propagated in a traveling wave is

Which of the following eye defects can be corrected using a cylindrical lens?

The time rate of loss of heat by a body is proportional to the

A concave mirror of radius of curvature 40cm forms a real image twice as large as the object. The object distance is

Water is a poor thermometric liquid because it

A ray of light which strikes a glass slab from air at normal incidence passes through the slab

Blowing air over a liquid aids evaporation by

The phenomenon that makes sound persist when its source has been removed is known as

Vibration in a stretched spring cannot be polarized because they are

The colours seen in soap bubbles are due to

When connected to a mains of 250V, the fuse rating in the plug of an electric device of 1 kW is

The eye controls the amount of light reaching the retina by adjusting the

An electric iron is rated 1000W, 230V. What is the resistance of its element?

The electromagnetic wave that can produce a heating effect on the environment is

From the generating station to each substation, power is transmitted at a very high voltage so as to reduce

The particle that is responsible for nuclear fission in a nuclear reactor is