Question

O yes QUESTION 2 A wave has period of 20 s. The frequency is Hz. QUESTION 3 A wave has frequency of 200 Hz. The period is s QUESTION 4 A rope wave travels at 20 m /s with a frequency of 4 Hz. The wavelength ism. Click Save and Submit to save and submit. Click Save All Answers to save all answers.

Answer 1

2.The frequency f=1/T=1/20=0.05 Hz.

3.The period=1/f=1/200=0.005 s.

4.The speed of the wave=$v=f\lambda$ . v=20 m/s and f=4 Hz. Therefore $\lambda =5 m.$

5.The velocity of the wave=$v=f\lambda =3Hz*2m=6 m/s.$

6.Rope waves are transverse.

7.Water waves are also transverse but are two dimensional unlike rope waves.

8 Sound waves are longitudinal.

9.The intensity of the bulb 2 m away=$I=I_{0}/4\pi r^{2}=60 W/16\pi =1.2 W/m^{2}$.

10.Intensity=I=$I=I_{0}/4\pi r^{2}=60 W/144\pi =0.13 W/m^{2}$.

11.The fraction of energy absorbed=(50 million square miles)/(93 million miles)²=6*10^-9 .

12.We have the relation $\beta =(10 dB)logI/I_{0}$ . Now $\beta+3 =(10 dB)logI'/I_{0}$ .

Subtracting the 2 equations we obtain $logI'/I=0.3$ i.e $I'=2I$.

13.In the same way as in the previous case $I'=10I$.

14 Here $I'=10^{10}I.$

15. The devices are using constructive interference,

16.The devices are using destructive interference.

17.The frequency measured is greatest when the source is moving towards the receiver. Therefore the correct answer is the the third one i.e 1034 Hz.