JAMB PRACTICE FRIDAY JUNE 4

How can energy loss be minimized through Eddy-current?

• By using high resistance wire

• By using insulated soft iron wires

• By using low resistance wires

• By using turns of wires

From the diagram above, calculate the energy stored in the capacitor

• $4.0\times10^{-2}\ J$

• $4.0\times10^{-4}\ J$

• $8.0\times10^{-4}\ J$

• $8.0\times10^{-2}\ J$

Which of the following operations can be used to convert an alternating current dynamo into a direct current dynamo

• number of turns in the coil is increased

• strength of the field magnet is increased

• slip rings are replaced with split ring commutator

• coil is wound on a soft iron armature

The net capacitance in the circuit above is

• 8.0 µF

• 6.0 µF

• 4.0 µF

• 2.0µF

The instrument used to measure the pressure of a gas is

• barometer

• thermometer

• hygrometer

• manometer

A man of mass 50kg ascends a flight of stains 5m high in 5 seconds. If acceleration due to gravity is 10ms⁻²

the power expended is

• 100 W

• 200 W

• 400 W

• 500 W

A radio station broadcast at a frequency of 600KH_Z. If the speed of light in air is 3 × 10⁸ ms⁻¹. Calculate the wavelength of the radio wave

• 2.20 × 10³ m

• 5.0 × 10² m

• 5.0 × 10⁵ m

• 11.8 × 10¹¹ m

The S.I unit of moment of a force is

• Nm

• kgms^-1

• Nm^-1

• Jm

A block and tackle pulley arrangement has 6 pulleys in which an effort of 50N supports a load of 200N, calculate the efficiency of the machine

• 80.0%

• 76.6%

• 66.7%

• 60.7%

Calculate the height of the image formed by a pinhole camera of length 12cm used to photograph an object 60cm away from the hole and 70cm high

• 10 cm

• 16 cm

• 5 cm

• 14 cm