Weight of an object on the Moon is about _____ of its weight on Earth.
A. 1/4
B. 1/2
C. 1/8
D. 1/6
Answer: Option D
Solution (By JKSSB Mock Tests)
Moon's gravity is about 1/6th of Earth's gravity. So weight (mg) is 1/6 of Earth weight. Mass remains same. g_moon ≈ 1.62 m/s², g_earth ≈ 9.8 m/s², ratio ≈ 1/6. Common fact in space science.
A student measures the length of a rod as 3.50 cm using a vernier caliper with least count 0.01 cm. The number of significant figures in this measurement is:
Explanation:
The measurement 3.50 cm has three significant figures. All non-zero digits (3,5) are significant, and the trailing zero after the decimal point is also significant as it indicates precision of the measuring instrument. The least count of 0.01 cm confirms that the measurement is precise to hundredths place. Significant figures reflect measurement reliability. Exam tip: Trailing zeros after decimal are always significant; leading zeros are never significant. This concept is crucial for error analysis in experimental physics questions.
Explanation:
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.
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