The length of a copper rod at 20°C is found to be 150cm when measured with a steel scale which gives correct reading at this temperature.What length of the same copper rod be found when measured with the same rod at 60°C?

A steel tape 1m long is correctly calibrated for a temperature of 27.0 ^@C . The length of a steel rod measured by this tape is found to be 63.0 cm on a hot day when the temperature is 45.0 ^@C . What is the actual length of the steel rod on that day? What Is the length of the same steel rod on a day when the temperature is 27.0 ^@C ? Coefficient of linear expansion of steel = 1.20xx10^-5 K^-1 .

A brass rod of length 50 cm and diameter 3.0 mm is joined to a steel rod of the same length and diameter. What is the change in length of the combined rod at 250 ^@C , if the original lengths are at 40.0 ^@C ? Is there a ‘thermal stress’ developed at the junction? The ends of the rod are free to expand (Co-efficient of linear expansion of brass = 2.0 xx 10^-5K^-1 steel = 1.2 xx 10^-5 K^-1) .

Explain why: n optical pyrometer (for measuring high temperatures) calibrated for an ideal black body radiation gives too low a value for the temperature of a red hot iron piece in the open, but gives a correct value for the temperature when the same piece is in the furnace

Two tuning forks when sounded together give 4 beats per second.if one of them is in unison with 96 cm length of a monochord under constant tension and the other with 97 cm length of the same string,find the frequencies of the fork.

A large steel wheel is to be fitted on to a shaft of the same material. At 27 ^@C , the outer diameter of the shaft is 8.70 cm and the diameter of the central hole in the wheel is 8.69 cm. The shaft is cooled using ‘dry ice’. At what temperature of the shaft does the wheel slip on the shaft? Assume coefficient of linear expansion of the steel to be constant over the required temperature range: a_ steel = 1.20 xx 10^-5K^-1 .

A zinc rod is measured by means of a brass scale (Which is correct at 0°C ) and is found to be 1.0001 metre long at 10°C .What is actual length of the rod at 0°C ?( alpha forZn= 29*10^-6/°C , alpha for brass= 19*10^-6/°C ).

which of the following cylindrical rods will conduct most heat,when their ends are maintained at the same steady temperature?

A rod of 2 cm in height is held in front of a convex lens. The, image formed at a distance 60 cm and object at 10 cm from the mirror. What is the focal length of the lens ?

A sphere ,a cubeand a thin circular plate,all made of the same meteriel and having the same mass are initially heated to a temperature of 200°C .Which of them will cool fastest and which one slowest when left in air at room temperature?

Assume the thermal conductivity of copper is 4 times that of brass.Two rods of copper and brass having the same length and cross section are joined end to end.The free and end of copper is at 0°C and the free end of brass is at 100°C.Calculate the temperature of the junctionof thw two rods at equilibirum.