User talk:Mathilde corazon/sandbox

Question 11Back to Top Question:  Frequency of a wave motion is 250 Hz. What is its time period?

Answer:   Frequency  = 250 Hz

Question 12Back to Top Question:  Define frequency. What is the frequency of a wave with a time period of 0.05 seconds?

Answer:   Frequency is defined as the waves passing through a point in one second.

Frequency= 20 Hertz

Question 13Back to Top Question:  A sound wave travelling in air has a wavelength of 1.6x10-2 m. If the velocity of sound is 320 m/s, calculate the frequency of sound.

Answer:   Wavelength of sound (l) = 1.6x10-2 m Velocity of sound (v) = 320 m/s

Frequency = 20 x 104 hertz

Question 17Back to Top Question:  The wavelength and velocity of red light is 7000 and 3x108m/s respectively. Calculate its frequency and time period.

Answer:   Wavelength  = 7000 = 7000 x 10-10m (1 =10-10 m) = 7 x 10-7m velocity (v) = 3 x 108 m/s

= 0.4281015 = 4.281014 Hz

= 0.002 x 10-12 s

Question 19Back to Top Question:  An observer stands at a distance of 850 m from a cliff and fires a gun. After what time gap will he hear the echo, if sound travels at a speed of 350 m s-1 in air?

Answer:   v =

= = 4.86 s

FORCES