Q: Which of the following is an example of thermoplastics?

A: Bakelite

B: Melamine

C: PVC

D: none of these



Correct Option: C  [ PVC ]

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Q: The layer of the atmosphere in which Radio Waves are reflected back is called:

A: Exosphere

B: Ionosphere

C: Troposphere

D: Stratosphere



Correct Option: B  [ Ionosphere ]

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Q: What is the frequency range of audible waves?

A: 20 to 20000 Hz

B: 21000–24000 Hz

C: 25000–30000 Hz

D: 31000–40000 Hz



Correct Option: A  [ 20 to 20000 Hz ]

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Q: The number of milk teeth in man is

A: 28

B: 29

C: 20

D: 12



Correct Option: C  [ 20 ]

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Q: Growth hormone is produced by :

A: Bones

B: Pituitary gland

C: Thyroid gland

D: Adrenal gland



Correct Option: B  [ Pituitary gland ]

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Q: Noise levels in residential areas should not exceed:

A: 30 decibels

B: 100 decibels

C: 85 decibels

D: 55 decibels



Correct Option: D  [ 55 decibels ]

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Q: The age Of trees is determined by its

A: height

B: girth

C: general appearance

D: growth rings



Correct Option: D  [ growth rings ]

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Q: The sun is seen before the actual sunrise because of:

A: re?ection

B: refraction

C: scattering of light

D: rectilinear propagation of light



Correct Option: B  [ refraction ]

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Q: Which of the following is not a property of heavy water ?

A: Boiling point of heavy water is lower than that of ordinary water

B: density of heavy water is higher than that of ordinary water

C: freezing point of heavy water is higher than that ordinary water

D: it produces corrosion



Correct Option: A  [ Boiling point of heavy water is lower than that of ordinary water ]

Remark:


Q: Shadows are formed when a __________ object comes in the path of light.

A: Opaque

B: Transparent

C: Luminous

D: Translucent



Correct Option: A  [ Opaque ]

Remark:
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