Identify the incorrect statement regarding the human eye.
A. The retina acts as the screen where images are formed.
B. The pupil regulates the amount of light entering the eye.
C. The image formed on the retina is virtual and erect.
D. The cornea provides most of the eye's refractive power.
Answer: Option C
Solution (By JKSSB Mock Tests)
The eye lens is a convex (converging) lens. It converges light rays to form a real and inverted image on the retina. The brain processes this signal and flips it so we perceive the world as erect. All other statements are functionally correct. The cornea does indeed do about two-thirds of the focusing.
Explanation:
Law of conservation of energy states total energy (all forms) is conserved in isolated systems. For mechanical energy (KE + PE) to be conserved, only conservative forces (like gravity, spring) must act; non-conservative forces (friction) convert mechanical energy to heat. Option C precisely states this condition. Options A and B are incorrect as KE and PE individually vary. Option D is false as thermal energy can exist. Memory tip: 'Mechanical energy conserved ⇔ no non-conservative work'. This nuanced understanding is critical for energy problems in competitive exams, where distractors often omit the conservative force condition.
Explanation:
Power negative means concave lens. f = 1/P (in metre) = 1/(-2.5) = -0.4 m = -40 cm. So concave lens of focal length 40 cm. Focal length negative for concave.
Explanation:
Electric fields deflect charged particles via Coulomb forces (F=qE), and magnetic fields deflect moving charged particles via Lorentz forces (F=qvB). Gamma rays are purely high-energy electromagnetic photons. Because they lack any electrical charge (q=0), both electric and magnetic forces on them are exactly zero. Therefore, they pass through fields completely un-deflected. R explains A perfectly.
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