Q.

The equation of a wave travelling on a string is y = sin [20 πx + 10 πt], where x and t are distance and time in SI units. The minimum distance between two points having the same oscillating speed is :          [2025]

1 5.0 cm  
2 20 cm  
3 10 cm  
4 2.5 cm  

Ans.

(1)

k=20π=2πλ  λ=10 cm

Minimum distance between 2 points having same speed is λ2.

Minimum distance =λ2=5 cm