The phenomenon of total internal reflection requires the light to travel from:
A. Glass to air
B. Any medium to vacuum
C. Air to glass
D. Water to glass
Answer: Option A
Solution (By JKExamLibrary)
Total internal reflection (TIR) occurs only when light travels from denser medium to rarer medium (e.g., glass to air, water to air) and angle of incidence exceeds critical angle. Air to glass (A) causes refraction toward normal; water to glass (C) may or may not cause TIR depending on refractive indices; vacuum is rarer than any medium but TIR requires denser→rarer. Memory aid: 'TIR condition: denser→rarer AND i > θ_c'. This optics condition question is frequently tested in competitive exams. Always verify both conditions (medium order and angle) for TIR; competitive exams often test common misconceptions about direction of travel.
Explanation:
g = GM/R², where M is mass of Earth, R radius, G universal constant. It does not depend on mass of falling object (Galileo's experiment). Earth's rotation causes slight variation but surface g is primarily determined by M and R. So mass of Earth is factor.
Explanation:
Electric generator (dynamo/alternator) works on electromagnetic induction: mechanical rotation induces emf. Motor does opposite. Transformer changes voltage. Battery converts chemical to electrical.
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