NABTEB

Distinguish between intrinsic and extrinsic semi conductors and give TWO examples of each. – NABTEB QUESTION

If conduction in material results only from the electron movement from valence to conduction band, it is called an intrinsic…

4 years ago

Describe an experiment to measure the specific heat capacity of a solid. – NABTEB QUESTION

The specific heat capacity of a solid in the form of a metal block can be determined by an electrical…

4 years ago

Explain why evaporation causes cooling and give the factors which affect its rate. – NABTEB QUESTION

The molecules of the liquid have an average velocity or average kinetic energy which increases with temperature. Molecules near the…

4 years ago

Explain using kinetic/molecular theory of matter why solid aluminium will change to liquid at 660°C without change in its temperature. – NABTEB QUESTION

Molecules of solid are in fixed position in the crystalline structure. They are held together by intermolecular forces. This constraint…

4 years ago

Mention Two sources of energy loss in a transformer and how they can be reduced. – NABTEB QUESTION

Two forms of energy loss in a transformer are: 1. eddy current 2. heat loss (1²R) / Joules heat or…

4 years ago

Name two electrical devices whose operation is based on the laws of electromagnetic induction. – NABTEB QUESTION

Two electrical devices whose operation is based on the laws of electromagnetic induction are: i. the transformer ii. the generator…

4 years ago

State Lenz’s law of electromagnetic induction – NABTEB QUESTION

Lenz’s law stats that: The induced current or (E.M.F.) always flows in such a direction as to oppose the change…

4 years ago

State faraday’s law of electromagnetic induction – NABTEB QUESTION

Faraday’s Law of electromagnetic induction states that: i. Whenever there is a change in the magnetic flux linked by a…

4 years ago

Explain what is meant by Doppler’s effect. – NABTEB QUESTION

Doppler’s effect can be defined as the change in the frequency of sound heard by an observer due to the…

4 years ago

Explain what is meant by echo and discuss how it can be used to measure the velocity of sound in air and the depth of the ocean. – NABTEB QUESTION

An echo is the sound heard after the reflection of the sound waves from a plane solid surface (hard surface).…

4 years ago