Answer:
Explanation:
velocity of sound in air at 20⁰C is 343 m /s
velocity of sound in water at 20⁰C is 1481 m /s
The wavelength of the sound is 2.86 m in the air so its frequency
= 343 / 2.86 = 119.93 .
This frequency of 119.93 will remain unchanged in water .
wavelength in water = velocity in water / frequency
= 1481 / 119.93
= 12. 35 m .
Answer:
i. + 22.5 m ii. 4.0 m
Explanation:
i. Image distance
Using the lens formula
1/u + 1/v = 1/f where f = focal length = + 18.0 m, u = object distance = distance of shark away from lens = + 90.0 m and v = image distance from lens = unknown
So, we find v
1/v = 1/f - 1/u
= 1/+18 - 1/+90
= (5 - 1)/90
= 4/90
v = 90/4
= + 22.5 m
So the image is real and formed 22.5 m away on the other side of the lens.
ii Length of Shark
Using the magnification formula, m = image height/object height = image distance/object distance. image height = 1.0 m where object height = length of shark.
m = image distance/object distance
= v/u
= +22.5/+90
= 0.25
0.25 = image height/object height
So,
object height = image height/0.25
= 1.0 m/0.25
= 4.0 m
So, the length of the shark is 4.0 m
The pressure of the air inside the balloon is higher than outside, and when you pop the balloon, the high pressure air expands quickly and makes a popping sound.
