The defect of vision in which a person cannot see nearby objects clearly is
A. Hypermetropia
B. Presbyopia
C. Myopia
D. Astigmatism
Answer: Option A
Solution (By JKSSB Mock Tests)
Hypermetropia (farsightedness): near point farther away, difficulty seeing close objects. Corrected with convex lens. Myopia: distant objects blurry. Presbyopia due to aging. Astigmatism due to irregular cornea.
Assertion (A): A fuse wire must have a high resistance and a low melting point. Reason (R): This ensures it melts quickly and breaks the circuit when an excessively high current flows.
A.A is false but R is true.
B.Both A and R are true but R is NOT the correct explanation of A.
C.Both A and R are true and R is the correct explanation of A.
Explanation:
A fuse is a safety device. It must have a relatively high resistance so that it produces heat quickly when a large current passes through (H = I²Rt). It must have a low melting point so that this heat causes it to melt immediately, breaking the circuit and protecting appliances. Thus, both A and R are true, and R explains A.
Explanation:
Maximum binding energy/nucleon ≈ 8.8 MeV at iron-56, making it most stable. Lighter nuclei release energy via fusion; heavier via fission. Memory tip: 'Iron peak: most stable nucleus; fusion before, fission after'. Nuclear physics concept frequently tested in competitive exams.
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