The specific heat capacity of a substance is defined as the amount of heat required to:
A. Vaporize 1 kg of the substance at its boiling point
B. Raise the temperature of 1 kg of the substance by 1°C
C. Melt 1 kg of the substance at its melting point
D. Raise the temperature of 1 g of the substance by 1°C
Answer: Option B
Solution (By JKSSB Mock Tests)
Specific heat capacity c is defined as heat required to raise temperature of unit mass (1 kg in SI) by 1°C (or 1 K). Formula: Q = mcΔT. Option D describes specific heat in cgs units (cal/g°C), but SI definition uses kg. Options A and C describe latent heats. Memory aid: 'Specific heat = per kg per degree'. This precise definition is crucial for calorimetry problems. Competitive exams often test unit awareness (kg vs g) to distinguish careful students. Always note the mass unit in the definition context.
Explanation:
Hypermetropia (farsightedness): near point farther away, difficulty seeing close objects. Corrected with convex lens. Myopia: distant objects blurry. Presbyopia due to aging. Astigmatism due to irregular cornea.
Explanation:
Pressure = Force/Area. Force = mass × acceleration, dimensions [MLT⁻²]. Area = L². So pressure = [MLT⁻²]/[L²] = [ML⁻¹T⁻²]. This is also the dimension of stress. Common exam trap: confuse with energy density which is also [ML⁻¹T⁻²].
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