Paheli took a wire of length 10 cm. Boojho took a wire of 5 cm of the same material and thickness. Both of them connected the wires as shown in the circuit given in Figure. The current flowing in both circuits is the same. Will, the heat produced be the same if the wires taken by them are of equal lengths but of different thicknesses? Explain.
Q. A power line lies along the east west direction and carries a current of 10ampere.The force per metre due to earths magnetic field of 10^xN/m .The value of x is
Q.A composite block is made of slabs A, B, C, D and E ofdifferent thermal conductivities (given in terms of a constantK)andsizes (givenin terms of length. L) as shown in thefigure. All slabs are of same with. Heat Q flows only from left to right through the blocks. Then, in steady state
heat flown trough A and E slabsare same
heat flow through slab e ismaximum
temperature difference across slab E is smallest
heat flow through C = heat flow through B + heat flowthrough D
Q. Ice starts forming in lake with water at 0∘ C and when the atmospheric temperature is −10∘ C . If the time taken for 1 cm of ice be 7 hours, then the time taken for the thickness of ice to change from 1 cm to 2 cm is
Q. A rod of 40 cm in length and temperature difference of 80∘ C between its two ends. Another rod B of length 60 cm and of temperature difference 90∘ C, have the same area of cross-section. If the rate of flow of heat is the same, then the ratio of their thermal conductivities will be
Q. 20 gm ice at −10oC is mixed with m gm steam at 100oC. Minimum value of m so that finally all ice and steam converts into water. (Use Sice=0.5cal/gmoC, Swater=1cal/gmoC, L(melting)=80 cal/gm and L (vapourization)=540 cal/gm)
