Q: An endoscope is used by a physician to view the internal parts of a body organ. It is based on the principle of:

A: refraction of light

B: reflection of light

C: total internal reflection of light

D: dispersion of light



Correct Option: C  [ total internal reflection of light ]

Remark:

Explanation: An endoscope works on the principle of total internal reflection of light. It uses optical fibers to transmit light into the body and carry the reflected image back to the observer. This allows physicians to view internal organs without surgery.


Q: To an astronaut in space, the sky appears to be:

A: Red

B: White

C: Dark

D: Blue



Correct Option: C  [ Dark ]

Remark:


Q: The stars twinkle at night because:

A: they emit energy

B: of diffraction

C: of refraction

D: of reflection



Correct Option: C  [ of refraction ]

Remark:

Explanation: Stars appear to twinkle at night due to the refraction of light by the Earth's atmosphere. As starlight passes through different layers of air with varying densities, its path bends continuously, causing the light’s intensity and position to appear to change, creating the twinkling effect.


Q: In a society the growth and development that meets the current human needs and also conserves natural resources for future generations is known as:

A: Green economy

B: Holistic development

C: Sustainable development

D: Subsistence agriculture



Correct Option: C  [ Sustainable development ]

Remark:

Sustainable Development refers to growth that meets the needs of the present without compromising the ability of future generations to meet their own needs. It aims to balance economic progress, social equity, and environmental protection by conserving natural resources and reducing pollution for long-term ecological stability.

  • Green economy: Focuses mainly on eco-friendly industries.
  • Holistic development: Emphasizes overall human and social growth.
  • Subsistence agriculture: Involves farming mainly for self-consumption.


Q: The weight of a body at the centre of the earth is:

A: zero

B: infinite

C: same as at other places

D: none of these



Correct Option: A  [ zero ]

Remark:

Explanation: The weight of a body at the centre of the Earth is zero because the gravitational forces from all directions cancel each other out. Although the body still has mass, it experiences no gravitational pull, resulting in zero weight.


Q: Which one of the following is a chemical change?

A: Melting of ice

B: Magnetising of Iron

C: Burning of coal

D: None of these



Correct Option: C  [ Burning of coal ]

Remark:
A chemical change, also called a chemical reaction, happens when substances combine or break apart to form entirely new substances with different properties.


Q: What is condensation?

A: Change of Solid into liquid

B: Change of vapour into liquid

C: Change of Liquid into Gas

D: None of these



Correct Option: B  [ Change of vapour into liquid ]

Remark:


Q: What is the unit for measuring the intensity of sound ?

A: Decibel

B: Coulomb

C: Henry

D: Hertz



Correct Option: A  [ Decibel ]

Remark:

Explanation: The intensity of sound is measured in decibels (dB). The decibel is a logarithmic unit that expresses the ratio of a sound’s intensity compared to a reference level (usually the faintest sound the human ear can detect, known as the threshold of hearing). The higher the decibel value, the louder the sound. For example, normal conversation is around 60 dB, traffic noise is about 80–90 dB, and sounds above 120 dB can cause pain or hearing damage.


Q: The addition of gypsum to Portland cement helps in:

A: increasing the strength of cement

B: rapid setting of cement

C: preventing rapid setting of cement

D: reducing in the cost of cement



Correct Option: C  [ preventing rapid setting of cement ]

Remark:


Q: The longest bone in the human body is:

A: Ulna

B: Humerus

C: Femur

D: Tibia



Correct Option: C  [ Femur ]

Remark:

Explanation: The femur is the single bone of the thigh region and extends from the hip joint to the knee joint. It supports the body’s weight during standing, walking, and running. The femur is the longest, heaviest, and strongest bone in the human skeleton. It articulates with the pelvic girdle at its proximal end (head of femur fits into the acetabulum of the pelvis) and with the tibia and patella at the distal end.

Average Length: Approximately 45 cm (about 1/4 of body height).
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