All 7 questions from the Post-UTME Screening (Post-UTME) Physics 2012 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.
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A man stands on a spring scale placed in a lift. The lift descends at constant velocity as a result, the scale reads a weight
At constant velocity (zero acceleration), the normal (scale) force equals the man's true weight.
A load of 5N gives an extension of 0.56cm in a wire which obeys Hook's Law. What is the extension caused by a load of 20N?
By Hooke's law, extension is proportional to load: 0.56 x (20/5) = 2.24cm.
In what range of temperature is the expansion of water anomalous?
Water's anomalous expansion classically occurs between 0 and 4 degrees C; the closest listed option, though not an exact match, is presented with reduced confidence given possible scan/option transcription issues.
Change of state is accompanied by a change of
A change of state involves a change in volume (density) and heat content (latent heat), while temperature itself remains constant during the phase change.
A metal cube of volume V and linear expansivity (alpha) is heated through a temperature rise of T. The increase in volume of the cube is
Volumetric expansivity is approximately 3 times the linear expansivity, so the volume increase = 3(alpha)VT.
Which of the following arrangements gives the electromagnetic radiation in the ascending order of wavelength?
This item's exact intended ordering (ascending wavelength vs ascending frequency) was ambiguous in the scan; option A is presented as the closest match to a recognizable increasing-frequency sequence, flagged for uncertainty.
Which of the following is used to slow down fast moving neutrons in a nuclear reactor?
A moderator such as a graphite block is used to slow down fast neutrons in a nuclear reactor (boron rods are control rods, which absorb neutrons).
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