They hysteresis loss for a speciment of iron weighing 12 kg is equivalent to `300 J m^-3 cyc^-1`. Find the loss of energy per hour at 50 cycles `s^-1`. Given, density of iron ` = 7,500 kg m^-3`

A transformer is working on 220V.50 Hz a.c. supply. The iron core of the transformer has a mass of 8.4 kg.. From the plot of B-H loop for the core, it is found that area of hte loop is 480 J m^-3 . If the density of iron is 7,500 kgm^-3 , find the loss of energy in the core of transformer in 1 hour.

In a test experiment on a model aeroplane in a wind tunnel, the flow speeds on the upper and lower surfaces of the wing are 70 m s^-1 and 63 m s^-1 respectively. What is the lift on the wing if its area is 2.5 m^2 ? Take the density of air to be 1.3 kg m^-3

An iron smaple having mass 8.4 kg is repeatedly taken over cycles of magnetisation and demagnetisation at a frequency of 50Hz. It is found that energy of 3.2 J is dissipated as heat in the sample in 30 minutes. If the denstiy of iron is 7200 kg m^-3 , calculate the value of energy dissipated per unit volume per cycle in the iron sample.

The thicknes of a metallic tube is 1 cm and the inner diameter of the tube is 12 cm. Find the mass of 1 m long tube, if the density of the metal be 7.8 g//cm^3 .

Two narrow bores of diameters 3.0 mm and 6.0 mm are joined together to form a U-tube open at both ends. If the U-tube contains water, what is the difference in its levels in the two limbs of the tube ? Surface tension of water at the temperature of the experiment is 7.3xx 10^-2 N m^-1 '. Take the angle of contact to be zero and density of water to be 1.0xx 10^3 kg m^- 3 ( g = 9.8 m s^-2 ) .

What is the absolute and gauge pressure of the gas above the liquid surface in the tank shown in the following figure? Density of oil = 820 kg m^-3 , density of mercury = 13.6 xx 10^3 kg m^-3 , 1 atmosphere pressure = 1.01 xx 10^5 pa .