Two electric bulbs have filaments of lengths `L` and `2L` diameters `2d` and d and emissivities `3e` and 4e If their temperatures are in the ratio 2:3 their powers will be in the ratio of .

Two Electric bulbs have filaments of lengths 1 and 21, diameters 2d and d. The emissivities of the bulbs are 3e, 4e with temperatures in the ratio 2 : 3. Their radiant powers will be in the ratio

Two spherical bodies have radii R,2R and emissivities e,2e If the temperature ratio is 2:1 then the powers will be in the ratio .

Two bulbs have filaments of lengths, Emissi-vities and diameters in the ratio of 2 : 1. If ratio of their powers is 1 : 2 then, ratio of their temperatures is

Two objects A & B have exactly the same shape and are radiating the same power If their temperatures are in the ratio sqrt3 : 1 then the ratio of their emissivities is .

Two bodies of same shape, same size and same radiating power have emissivities 0.2 and 0.4 The ratio of their temperature is .

Two electric lamps A and B radiate the same power. Their filaments have the same diemensions, and have emissivities. e_(A) and e_(B) . Their surface tempratures are T_(A) an T_(B) . The ratio T_(A)//T_(B) will be equal to