The temperature of a black body is 500 and its radiation is of wavelength 600 . If the number of oscillators with energy is 100 , 000, calculate the number of oscillators in the black body with energy 1 . (Accoding to Max. Planck, the number of oscillators with energy ℎ at a particular frequency is given by = = − ( ⁄ ) = − ( ⁄ ) (10 Marks) (b) Calculate the peak wavelength of a black body's radiation if the black body is at a temperature of 20 , 000 . (5 Marks)

If a balloon is taken outside on a very cold day, what will occur?

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)

Calculate the first and second velocities of the car with four washers attached to the pulley, using the formulas v1 = 0.25 m / t1 , and v2 = 0.25 m / (t2 – t1) where t1 and t2 are the average times the car took to reach the 0.25 and the 0.50 meter marks. record these velocities, to two decimal places, in table e.