1)Ultrasound can penetrated tissue to depth approximately 200 times its wavelength. What is the approcimate depth of the penetration of ultrasound at a frequency of 5 MHz?

- 17 cm

-6.2 cm

-1.4 cm

-0.29 mm

2)A Heat engine operating between a pair of hot and cold reservoirs with respective temperatures of 500k and 200 K will have what maximum efficiency?

-60%

-50%

-40%

-30%

3) A steel wire, 150 m long at 10 deg. Celsius has a coefficient of linear expansion of (11x10^-6) / C . Give its change in the length as the temp changes from 10 deg. Celsius to 45 deg. Celsius.

- 12 cm

- 1.8 cm

- 0.65 cm

- 5.8 cm