A vernier caliper has 20 divisions on vernier scale matching 19 main scale divisions. If main scale division is 1 mm, least count is: MCQ with Answer and Explanation
Assertion (A): When ice floats in water, its approximately 1/10th volume remains outside the water. Reason (R): The density of ice is approximately 10% less than the density of water.
A.A is false but R is true.
B.Both A and R are true but R is NOT the correct explanation of A.
C.A is true but R is false.
D.Both A and R are true and R is the correct explanation of A.
Explanation:
The density of ice is about 900 kg/m³ (0.9 g/cm³), while pure water is 1000 kg/m³ (1.0 g/cm³). According to the principle of floatation, the fraction of volume submerged is the ratio of densities: ρ_ice / ρ_water = 0.9. This means 90% is submerged, leaving exactly 10% (1/10th) exposed above the surface. Reason R explains Assertion A.
Explanation:
When light passes from a rarer medium (air) to a denser medium (glass), its speed decreases due to the higher refractive index. Wavelength is directly proportional to speed, so it also decreases. However, the frequency depends only on the source of light and remains absolutely constant during refraction across any boundary.
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