The heating element of a heater is made of nichrome because it has MCQ with Answer and Explanation

The heating element of a heater is made of nichrome because it has
A. High resistivity, low melting point
B. Low resistivity, low melting point
C. High resistivity, high melting point
D. Low resistivity, high melting point
Answer: Option C
Solution (By JKExamLibrary)
Nichrome high resistivity generates more heat, high melting point avoids melting at high temperature.

This question belongs to: Science Physics

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Practice More Physics Questions

Question #1 Report Error
A block of wood floats in water with 60% of its volume submerged. In a liquid of density 0.8 g/cm³, the fraction of volume submerged will be:
A. 48%
B. 80%
C. 75%
D. 60%

Correct Answer: Option C


Explanation:
From floatation: ρ_wood/ρ_water = fraction submerged in water = 0.6. Thus ρ_wood = 0.6 g/cm³ (since ρ_water = 1 g/cm³). In new liquid (ρ_l = 0.8 g/cm³), fraction submerged f = ρ_wood/ρ_l = 0.6/0.8 = 0.75 = 75%. This uses the principle that fraction submerged equals density ratio. Memory aid: 'f = ρ_object / ρ_fluid'. Such comparative buoyancy problems test application of Archimedes' principle across scenarios, common in competitive exams. Always maintain consistent units (g/cm³ here simplifies calculation).

This question belongs to: Science Physics
Question #2 Report Error
An ultrasound wave has frequency 2 MHz. Time period is
A. 0.5 ms
B. 0.5 μs
C. 2 μs
D. 2 ms

Correct Answer: Option B


Explanation:
T = 1/(2×10⁶) = 0.5×10⁻⁶ s = 0.5 μs.

This question belongs to: Science Physics
Question #3 Report Error
The process of change from solid directly to vapour is called
A. Freezing
B. Melting
C. Condensation
D. Sublimation

Correct Answer: Option D


Explanation:
Sublimation: solid → gas without liquid phase. Example: camphor, naphthalene balls, dry ice (solid CO₂). Deposition is reverse. Latent heat of sublimation involved.

This question belongs to: Science Physics