EASY
Physics
IMPORTANT
Earn 100

A block of ice of mass M=13.44 kg slides on a horizontal surface. It starts with a speed of v=10 m/s and finally stops after moving a distance of s=30 m. What is the mass of ice (in grams) that has melted due to friction between the block and the surface? Latent heat of fusion of ice is Lf=80 cal/g

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Important Questions on Thermometry, Thermal Expansion and Calorimetry

HARD
Physics
IMPORTANT
A calorimeter of water equivalent 10 g contains a liquid of mass 50 g at 40°C. When m gram of ice at -10°C is put into the calorimeter and the mixture is allowed to attain an equilibrium, the final temperature was found to be 20°C. It is known that the specific heat capacity of the liquid changes with temperature as s=1+θ500 cal g-1 °C-1 where θ is the temperature in °C. The specific heat capacity of ice, water and the calorimeter remain constant and values are Sice=0.5 Cal g-1 °C-1; Swater=1.0 Cal g-1 °C-1 and latent heat of fusion of ice is Lf=80 Cal g-1 . Assume no heat loss to the surrounding and calculate the value of m in grams.
EASY
Physics
IMPORTANT

This question contains Statement 1 and Statement 2 Of the four choices given after the statements, choose the one that best describes the two statements.

Statement 1: The temperature dependence of resistance is usually given as R=R01+αΔt. The resistance of a wire changes from 100 Ω to 150 Ω when its temperature is increased from 27°C to 227°C. This implies that α=2.5×10-3/C.

Statement 2: R=R(1+αΔT) is valid only when the change in the temperature ΔT is small and ΔR=R-R0<<R0.

MEDIUM
Physics
IMPORTANT
100 g of water is heated from 30 °C to 50 °C. Ignoring the slight expansion of the water, the change in its internal energy is (Specific heat of water is 4184 J kg-1 K-1)
EASY
Physics
IMPORTANT

A wooden wheel of radius R is made of two semicircular parts (see figure). The two parts are held together by a ring made of a metal strip of cross sectional area S and length L. L is slightly less than 2πR. To fit the ring on the wheel, it is heated so that its temperature rises by ΔT and it just steps over the wheel. As it cools down to surrounding temperature, it presses the semicircular parts together. If the coefficient of linear expansion of the metal is α, and its Young's modulus is Y, the force that one part of the wheel applies on the other part is

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MEDIUM
Physics
IMPORTANT
The pressure that has to be applied to the ends of a steel wire of length 10 cm to keep its length constant when its temperature is raised by 100°C is (For steel, Young's modulus is 2×1011 N m-2 and coefficient of thermal expansion is 1.1×10-5 K-1)
EASY
Physics
IMPORTANT
A pendulum clock lose 12 s a day if the temperature is, 40°C and gains, 4 s a day if the temperature is, 20°C. The temperature at which the clock will show correct time, and the co-efficient of linear expansion (α) of the metal of the pendulum shaft are respectively :
EASY
Physics
IMPORTANT

An external pressure P is applied on a cube at 0°C so that it is equally compressed from all sides. K is the bulk modulus of the material of the cube and α is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by:

MEDIUM
Physics
IMPORTANT
A copper ball of mass 100 gm is at a temperature T. It is dropped in a copper calorimeter of mass 100 gm, filled with 170 gm of water at room temperature. Subsequently, the temperature of the system is found to be 75 °CT is given by: (Given: room temperature =30 °C, the specific heat of copper =0.1 cal gm-1°C-1)