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Question (31)

QN00211

Convection currents in liquids continue until —

(A) the liquid evaporates completely
(B) the entire liquid gets heated
(C) the colour disappears
(D) the flame stops producing light

Correct Answer: B

Explanation:

Heat spreads through the entire liquid.

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Question (32)

QN00212

Which of the following is NOT related to convection?

(A) Sea breeze
(B) Land breeze
(C) Rising smoke
(D) Heating of an iron spoon

Correct Answer: D

Explanation:

Heating of an iron spoon is conduction.

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Question (33)

QN00213

Why does cooler air from sea move towards land during daytime?

(A) Warm air above land rises upward
(B) Sea water evaporates quickly
(C) Land becomes cooler
(D) Sea breeze flows downward only

Correct Answer: A

Explanation:

Rising warm air creates low pressure over land.

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Question (34)

QN00214

Which of the following best explains convection in water?

(A) Water particles move due to density differences
(B) Heat travels without medium
(C) Water remains stationary during heating
(D) Heat flows only downward

Correct Answer: A

Explanation:

Differences in density cause water movement.

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Question (35)

QN00215

A teacher heats water in a beaker from below. Which region of water becomes hot first?

(A) Top layer
(B) Middle layer
(C) Bottom layer
(D) Entire beaker together

Correct Answer: C

Explanation:

The bottom layer receives heat directly.

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Question (36)

QN00216

Why is sea water cooler than nearby land during daytime?

(A) Water heats up more slowly than land
(B) Sea absorbs no heat
(C) Water reflects all sunlight
(D) Land contains no moisture

Correct Answer: A

Explanation:

Water takes longer to heat up.

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Question (37)

QN00217

Which device mainly works due to convection currents in air?

(A) Smoke chimney
(B) Mirror
(C) Steel ruler
(D) Wooden table

Correct Answer: A

Explanation:

Hot air and smoke rise through the chimney.

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Question (38)

QN00218

During nighttime near coastal areas, the sea remains warmer because water —

(A) cools faster than land
(B) cools more slowly than land
(C) absorbs no heat
(D) becomes solid at night

Correct Answer: B

Explanation:

Water loses heat more slowly.

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Question (39)

QN00219

In convection, the heated particles generally move —

(A) downward
(B) upward
(C) sideways only
(D) nowhere

Correct Answer: B

Explanation:

Heated particles become lighter and rise.

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Question (40)

QN00220

Which statement is correct about convection currents?

(A) They occur only in gases
(B) They occur due to actual movement of heated particles
(C) They transfer heat without any medium
(D) They occur only in solids

Correct Answer: B

Explanation:

Convection currents are formed by movement of particles.

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Question (31)

Convection currents in liquids continue until —

Explanation:

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Question (32)

Which of the following is NOT related to convection?

Explanation:

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Question (33)

Why does cooler air from sea move towards land during daytime?

Explanation:

Link:

Question (34)

Which of the following best explains convection in water?

Explanation:

Link:

Question (35)

A teacher heats water in a beaker from below. Which region of water becomes hot first?

Explanation:

Link:

Question (36)

Why is sea water cooler than nearby land during daytime?

Explanation:

Link:

Question (37)

Which device mainly works due to convection currents in air?

Explanation:

Link:

Question (38)

During nighttime near coastal areas, the sea remains warmer because water —

Explanation:

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Question (39)

In convection, the heated particles generally move —

Explanation:

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Question (40)

Which statement is correct about convection currents?

Explanation:

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