A 90°C
B 100°C
C 110°C
D 80°C
Explanation: Water boils at 100°C (373 K) at standard atmospheric pressure.
A Increases
B Decreases
C Remains constant
D First increases then decreases
Explanation: During phase change (melting), the temperature remains constant at the melting point.
A kg·m/s
B N·s
C Both A and B
D N/m
Explanation: Impulse = Force × time = N·s, and from momentum change it is also kg·m/s. Both are equivalent.
A 9 J
B 4.5 J
C 3 J
D 1.5 J
Explanation: KE = ½mv² = ½ × 1 × 9 = 4.5 J
A 8 km/s
B 3 km/s
C 11 km/s
D 7.9 km/s
Explanation: The orbital velocity near Earth\'s surface is v = √(gR) ≈ 7.9 km/s
Explanation: A single movable pulley provides a mechanical advantage of 2
A Same as initial
B Double
C Zero
D Half
Explanation: By conservation of momentum: mv - mv = 2mv\' → v\' = 0
Explanation: h = ½gt² → 80 = ½ × 10 × t² → t² = 16 → t = 4 s
A 50 mm
B 0.02 mm
C 1 mm
D 2 mm
Explanation: Pitch = distance moved per rotation = 1 mm (given), least count = 1/50 = 0.02 mm
A [MLT⁻²]
B [ML²T⁻²]
C [MLT⁻¹]
D [MLT]
Explanation: F = ma, so dimension of force = [M][LT⁻²] = [MLT⁻²]
A 49 N
B 8.2 N
C 16.3 N
D 32.7 N
Explanation: Weight on Moon = W/6 ≈ 49/6 ≈ 8.17 N ≈ 8.2 N
A Speed
B Distance
C Displacement
D Mass
Explanation: Displacement has both magnitude and direction, making it a vector quantity.
A 7.9 km/s
B 11.2 km/s
C 15.4 km/s
D 3.3 km/s
Explanation: Escape velocity = √(2gR) ≈ 11.2 km/s
A 20 N
B 16 N
C 4 N
D 36 N
Explanation: Buoyant force = weight in air - apparent weight = 20 - 16 = 4 N
A Glass
B Water
C Vacuum
D Diamond
Explanation: Light travels fastest in vacuum (c = 3 × 10⁸ m/s), which is the universal speed limit.
Explanation: Normal incidence means the ray is perpendicular to the surface, so angle of incidence = 0°
A Positive
B Negative
C Zero
D Infinity
Explanation: A concave lens is a diverging lens and has negative power.
A 10 Ω
B 5 Ω
C 2.5 Ω
D 40 Ω
Explanation: Doubling back halves the length and doubles the cross-section → R becomes R/4 = 10/4 = 2.5 Ω
A Same
B Double
C Four times
D Half
Explanation: R = ρL/A. If L→2L and A→A/2, new R = ρ(2L)/(A/2) = 4ρL/A = 4R
A Doubles
B Remains same
C Halves
D Quadruples
Explanation: C = ε₀A/d. If d is doubled, C becomes half.