The speed of light in vacuum is approximately MCQ with Answer and Explanation

Explanation:
Heat is energy transferred due to temperature difference.

Explanation:
For myopia, corrective lens forms image of distant object at far point. 1/f = 1/(-far point) - 1/(-∞) => -2 = -1/F => F = 0.5 m = 50 cm.

Explanation:
Seismograph detects and records ground motions caused by earthquakes, volcanic activity, or explosions. It measures seismic waves (P-waves, S-waves). Barometer detects pressure changes; hydrophone detects underwater sound; magnetometer detects magnetic fields. Memory tip: 'Seismo = earthquake (like seismology)'. This instrument-application question tests knowledge of geophysical tools, frequently examined in competitive exams. Always associate instrument names with their field of use: seismograph (geology), barometer (meteorology), etc.