The emissive power of sphere of area `0.02 m^2` is `0.5 kcal//s-m^2`. What is the amount of heat radiated by the spherical surface in 20 seconds?

The emissive power of a sphere of area 0.02m^2 is 0.5 kcal s^-1m^-2 . What is the amount of heat radiated by the spherical surface in 20 seconds.

A metal cube has each side 2.5 cm long and radiates 0.36 kcal//min . What is the emissive power of its surface? If the emissivity of its surface is 0.4, what would be the emissive power of the cube if it were perfectly black?

Emissive power of cube is 1000 J//m^2s and it · radiates heat at the rate 60 watt at that temperature. The length of each side of cube will be

If at any time, the displacement of a simple pendulum be 0.02 m, then its acceleration is 2 m/ s^2 . What is the angular speed of the pendulum at that instant?

The rate of emission of heat energy per unit area of an iron ball of radius 10 cm is 10J//m^2s s, then rate ·of emission of heat energy per unit area by a copper ball of radius 5 cm at same temperature will be ( emissivity of both the balls is same)

A charge of 15muC is given to hollow metallic sphere of radius 0.3m. Find the potential:- at the surface of sphere

A solid sphere of mass 2 kg is resting inside a cube as shown in the figure. The cube is moving with a velocity v=(5t hati+2thatj)"m"//"s". Here t is the time in second. All surface are smooth. The sphere is at rest with respect to the cube. What is the total force exerted by the sphere on the cube? (Take g=10" m"//"s"^(2) )

A metal cube of each side 0.05 m long emits 0.6k cal in 80 seconds, Calculate the emissive power of its surface.

A body of mass 2 kg is being dragged with uniform velocity of 2 m / s on a rough horizontal plane. The coefficient of friction between the body and the surface is 0.20. The amount of heat generated in 5 sec is . (4.2"joule"//cal and g=9.8 m//s^(2))