Radiation

Watch the video and answer the multiple choice questions. In which of the following processes does not require a medium for heat transfer? radiation conduction both a and b convection The heat from the Sun reaches the Earth by the process of …………….. . conduction radiation convection both conduction and radiation The temperature of four identical bodies A, B, C and D are 600°C, 700°C, 800°C, and 900°C, respectively. Which of them will radiate the maximum heat to its surroundings? A B C D If the temperature of a hot object is increased, then the heat radiated by it will …………….... decrease increase will remain constant may increase or decrease Which of the following is the fastest mode of heat transfer? radiation conduction convection all of the above, as they transfer heat at same rate Which of the following radiates maximum heat? A lit candle A mug of hot coffee A heated electric iron The Sun The energy which gets transferred by radiation is called ……………... energy. transmitted absorbed reflected radiant Two tin cans, one white and the other black in colour, containing equal amounts of water, at equal temperatures, are kept in the sun. The water in which can will warm up first? The black can The white can Both the cans together Neither of the cans will warm up Dark-coloured objects radiate _ light-coloured objects, under the same circumstances. More heat than Less heat than The same amount of heat as Sometimes less and sometimes more heat than _ clothes are worn in summer and _ clothes are worn in winter. Light-coloured, dark-coloured Dark-coloured, light-coloured Red-coloured, white-coloured Black –coloured, white- coloured When radiant heat falls on an object, its temperature increases due to _ heat. relfected absorbed transmitted both reflected and absorbed A solar cooker is painted in _ colour so that it can absorb maximum radiant heat coming from the sun. white green black pink Choose the correct statement. When radiant heat falls on an object, it’s completely absorbed. When radiant heat falls on an object, it’s partly absorbed, partly reflected, and may be partly transmitted. When radiant heat falls on an object, it’s completely reflected. When radiant heat falls on an object, it’s completely transmitted. Two tin cans, one white and the other black in colour, containing equal amounts of hot water at equal temperatures, are kept in the shade to cool down. The water in which can will cool down faster? The black can The white can Both the cans together Neither of the cans will cool down