The pitch of a sound becomes higher if MCQ with Answer and Explanation

Explanation:
Total time of flight T = 2u/g => u = gT/2 = 10×6/2 = 30 m/s. Max height H = u²/(2g) = 900/20 = 45 m. Alternatively, time to max height = 3 s, H = ½g t² = ½×10×9 = 45 m.

Explanation:
kWh used for billing.

Explanation:
Visible spectrum: red ~700 nm, orange, yellow, green, blue, indigo, violet ~400 nm. Red has longest wavelength, lowest frequency. Violet shortest wavelength, highest frequency. Remember VIBGYOR.