WAEC 2022 PHYSICS

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PHYSICS OBJ

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11-20: CAACABBBBC

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(1)

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(2)

(i) They are pure semiconductors with impurities less than 1 and have tetravalent crystals

(ii) Presense of mobile charge carrier is intrinsic property of material

(iii) No doping or addition of impurities required.

(3)

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(4)

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(5a)

A geostationary satellite is an earth-orbiting satellite, placed at an altitude of approximately 35,800km directly over the equator, that revolves in the same direction which the earth rotates.

(5b)

(PICK ANY TWO)

(i) Gas laser

(ii) Solid-state laser

(iii) Liquid laser

(iv) Semiconductor laser

(6a)

The S.I unit is watt per steradian (W/sr)

(6b)

(i) As the temperature of the black body increases, the peak wavelength decreases.

(ii) The total energy being radiated is the area under the graph

(7)

(8ai)

The law of inertia states that a body will continue in its present state of rest or if it is in motion, will continue to move with uniform speed in a straight line unless it is acted upon by a force.

(8aii)

When the brakes of the moving vehicle are suddenly applied, or the passengers jerks forward as thet tend to continue in a straight line. The seat belt helps to provide a backward force and reduces injuries.

(8bi)

The moment of a force about a fixed point is the product of the force and the perpendicular distance at the point to the line of action of the force.

(8bii)

(I) Draw the Diagram