Central Exam — General Science
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Showing 171–180 of 207 questions
Q.171 Medium Physics
A block slides down a frictionless incline of angle 30°. What is its acceleration down the incline?
A 5 m/s²
B 8.66 m/s²
C 9.8 m/s²
D 10 m/s²
Correct Answer:  A. 5 m/s²
Explanation:

On a frictionless incline, a = g sin(θ) = 10 × sin(30°) = 10 × 0.5 = 5 m/s².

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Q.172 Medium Physics
A spring with spring constant k = 100 N/m is compressed by 0.1 m. What is the elastic potential energy stored?
A 0.5 J
B 1 J
C 5 J
D 10 J
Correct Answer:  A. 0.5 J
Explanation:

Elastic PE = ½kx² = ½ × 100 × (0.1)² = ½ × 100 × 0.01 = 0.5 J.

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Q.173 Medium Physics
Which phenomenon occurs when sound waves bend around obstacles?
A Reflection
B Refraction
C Diffraction
D Interference
Correct Answer:  C. Diffraction
Explanation:

Diffraction is the bending of waves around obstacles or through openings. This explains why we can hear sounds around corners.

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Q.174 Medium Physics
A light ray travels from air (n=1) into glass (n=1.5) at an incident angle of 30°. What is the refraction angle?
A 15°
B 19.47°
C 22.08°
D 30°
Correct Answer:  B. 19.47°
Explanation:

Using Snell's Law: n₁sinθ₁ = n₂sinθ₂. 1 × sin(30°) = 1.5 × sinθ₂. 0.5 = 1.5sinθ₂. sinθ₂ = 0.333. θ₂ ≈ 19.47°.

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Q.175 Easy Physics
Which color of visible light has the longest wavelength?
A Violet
B Blue
C Yellow
D Red
Correct Answer:  D. Red
Explanation:

The visible light spectrum ranges from violet (shortest wavelength ~400 nm) to red (longest wavelength ~700 nm). Red light has the longest wavelength among visible light.

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Q.176 Medium Physics
Two resistors of 4Ω and 6Ω are connected in series with a 10V battery. What is the total current?
A 1 A
B 2 A
C 10/6 A
D 10/4 A
Correct Answer:  A. 1 A
Explanation:

Total resistance = 4 + 6 = 10Ω. Using Ohm's law: I = V/R = 10/10 = 1 A.

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Q.177 Medium Physics
Which of the following is a non-ohmic conductor?
A Copper wire at constant temperature
B Tungsten filament in a light bulb
C Nichrome wire at constant temperature
D Silver wire at constant temperature
Correct Answer:  B. Tungsten filament in a light bulb
Explanation:

A tungsten filament's resistance changes significantly with temperature during operation, making it non-ohmic. Metals at constant temperature follow Ohm's law.

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Q.178 Medium Physics
What is the SI unit of magnetic flux?
A Tesla
B Weber
C Gauss
D Henry
Correct Answer:  B. Weber
Explanation:

The Weber (Wb) is the SI unit of magnetic flux, defined as Tesla × meter². 1 Wb = 1 T·m².

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Q.179 Medium Physics
A transformer has 100 turns in the primary coil and 500 turns in the secondary coil. If the primary voltage is 220V, what is the secondary voltage assuming 100% efficiency?
A 44 V
B 220 V
C 1100 V
D 2200 V
Correct Answer:  C. 1100 V
Explanation:

Using transformer equation: Vₛ/Vₚ = Nₛ/Nₚ. Vₛ = 220 × (500/100) = 220 × 5 = 1100 V.

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Q.180 Medium Physics
Which statement about alpha decay is correct?
A An alpha particle is a helium nucleus with 2 protons and 2 neutrons
B Alpha decay increases the atomic number
C Alpha particles have high penetration power
D Alpha decay produces beta particles
Correct Answer:  A. An alpha particle is a helium nucleus with 2 protons and 2 neutrons
Explanation:

An alpha particle is a helium-4 nucleus (₂He⁴) with 2 protons and 2 neutrons. Alpha decay decreases atomic number by 2 and mass number by 4. Alpha particles have low penetration power.

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