The particle with highest ionising power is MCQ with Answer and Explanation

Explanation:
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:
Time period T = 1/f = 1/200 = 0.005 s = 5 ms. Frequency is number of cycles per second. Relationship T = 1/f is fundamental. For 200 Hz, period is 5 milliseconds.

Explanation:
Moderator slows neutrons via elastic collisions, low absorption. Heavy water, graphite.