A body at 100°C is placed in contact with a body at 0°C. Heat flow stops when MCQ with Answer and Explanation
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Question #1
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A fuse in an electrical circuit is designed to:
Correct Answer: Option C
Explanation:
Fuse is a safety device with a wire that melts when current exceeds rated value, breaking the circuit and preventing damage from overcurrent/short circuits. It operates on Joule heating (I²R). Option A is opposite; C describes capacitor; D describes rectifier. Memory tip: 'Fuse = sacrificial overcurrent protector'. This practical application question tests knowledge of electrical safety devices, frequently examined in competitive exams. Always link fuse rating to circuit requirements: fuse current rating slightly above normal operating current.
Fuse is a safety device with a wire that melts when current exceeds rated value, breaking the circuit and preventing damage from overcurrent/short circuits. It operates on Joule heating (I²R). Option A is opposite; C describes capacitor; D describes rectifier. Memory tip: 'Fuse = sacrificial overcurrent protector'. This practical application question tests knowledge of electrical safety devices, frequently examined in competitive exams. Always link fuse rating to circuit requirements: fuse current rating slightly above normal operating current.
Question #2
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The ripple factor of a full wave rectifier is approximately
Question #3
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The dimensional formula of torque is the same as that of:
Correct Answer: Option A
Explanation:
Torque τ = r × F, so dimensions [L][MLT⁻²] = [ML²T⁻²]. Work W = F·d, dimensions [MLT⁻²][L] = [ML²T⁻²], identical. Momentum is [MLT⁻¹], force [MLT⁻²], power [ML²T⁻³]. Though torque and work have same dimensions, they are physically distinct: torque is vector (rotational effect), work is scalar (energy transfer). Memory tip: 'Torque and work share [ML²T⁻²]; but torque = rF sinθ, work = Fd cosθ'. This dimensional analysis question tests ability to compare quantities, frequently appearing in competitive exams. Always verify dimensions but remember physical context differs.
Torque τ = r × F, so dimensions [L][MLT⁻²] = [ML²T⁻²]. Work W = F·d, dimensions [MLT⁻²][L] = [ML²T⁻²], identical. Momentum is [MLT⁻¹], force [MLT⁻²], power [ML²T⁻³]. Though torque and work have same dimensions, they are physically distinct: torque is vector (rotational effect), work is scalar (energy transfer). Memory tip: 'Torque and work share [ML²T⁻²]; but torque = rF sinθ, work = Fd cosθ'. This dimensional analysis question tests ability to compare quantities, frequently appearing in competitive exams. Always verify dimensions but remember physical context differs.
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