NTA Abhyas JEE Main2020PhysicsWaves and SoundPractice
For simple harmonic vibrations y 1 = 8 c o s ω t y 2 = 4 c o s ( ω t + π 2 ) y 3 = 2 c o s ( ω t + π ) y 4 = cos ω t + 3 π 2 are superimposed on one another. The resulting amplitude and phase are respectively
Options
- A45 and tan - 1 ( 1 2 )
- B45 and tan - 1 1 3
- C75 and tan - 1 2
- D75 and tan - 1 ( 1 3 )
Correct answer
A. 45 and tan - 1 ( 1 2 )
Step-by-step solution
Resultant displacement along X - axis is x = y 1 - y 3 = 8 - 2 = 6 Resultant displacement along Y - axis is y = y 2 - y 4 = 4 - 1 = 3 Net displacement, r = x 2 + y 2 = 6 2 + 3 2 = 45 Also, tan θ = y x = 3 6 = 1 2