Practice Physics questions - general science mcq Online Quiz (set-1) For All Competitive Exams
Q-1) The normal temperature of human body on the Kelvin scale is
(a)
(b)
(c)
(d)
Q-2) The safest temperature for keeping food fresh in a refrigerator is
(a)
(b)
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(d)
Q-3) 5g ice at 0ºC is mixed with 5g of steam at 100ºC . What is the final temperature?
(a)
(b)
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Heat required by ice to raise its temperature to 100°C,
$Q_1 = m_1L_1 + m_1c_ 1Δϴ_1$ = 5 × 80 + 5 × 1 × 100 = 400 + 500 = 900 cal.
Heat given by steam when condensed,
$Q_2 = m_2L_2$ = 5 × 536 = 2680 cal as $Q_2 > Q_1$.
This means that whole steam is not even condensed.
Hence temperature of mixture will remain at 100°C.
Q-4) Which one of the colours has the longest wavelength?
(a)
(b)
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Q-5) When a piece of ice floating in a glass of water melts, the level of water will
(a)
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Q-6) When beams of red, blue and green lights fall on the same spot, the colour of the light becomes
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Q-7) Retina of the eye is comparable to which of the following parts of a traditional camera?
(a)
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Q-8) In scattering of light phenomenon, light falls on tiny particles absorbed by these tiny particles. Then these particles re-emit light in all directions.
- Intensity of scattered light, $I ∝ 1/λ^4$
- Greenish-blue appearance of sea water is due to scattering of light
- In a clear atmosphere of the earth, red colour scatters more than blue colour.
Which of the above statement(s) is /are true?
(a)
(b)
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The wavelength of the red colour is more than the blue colour. According to Reybergh's scattering formula scattering ∝ $1/4$
Thus, the light of short waves is scattered about ten times as the longer waves of red light.
Q-9) Which of the following is carried by the waves from one place to another ?
(a)
(b)
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Q-10) Long radio waves are reflected by which of the following layer of Earth’s surface?
(a)
(b)
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(d)