Thermodynamics Practice Level - 1 - Class 11 MCQ

Two holes of unequal diameters d1 and d2 (d1 > d2) are cut in a metal sheet. If the sheet is heated

Work done in converting 1 g of ice at - 10⁰C intostream at 100⁰ C is

Compared to a burn due to water at 100⁰C, a burndue to stream at 100⁰C is

Three liquids with masses m₁, m₂, m₃ are throughly mixed. If their specific heats are c₁, c₂, c₃ and their temperatures T₁, T₂, T₃, respectively, then the temperature of the mixture is

Two rods (one semi-circular and other straight) ofsame material and of same cross-sectional area arejoined as shown in Fig. The points A and B aremaintained at different temperatures. The ratio of theheat transferred through a cross section of a semicircularrod to the heat transferred through a crosssection of the straight rod in a given time is

A point source of heat of power P is placed at thecentre of a spherical shell of mean radius R. Thematerial of the shell has thermal conductivity K. Ifthe temperature difference between the outer andthe inner surface of the shell is not to exceed T, thenthe thickness of the shell should not be less than

Three rods of same dimensions are arranged as shownin Fig. They have thermal conductivities K₁, K₂ and K₃.The points P and Q are maintained at different temperatures for the heat of flow at the same rate along PRQ and PQ. Which of the following options is correct?

The coefficient of thermal conductivity of copper isnine times that of steel. In the composite cylindricalbar shown in Fig., what will be the temperature atthe junction of copper and steel?

Six identical conducting rods are joined as shown inFig. Points A and D are maintained at temperatures 200⁰C and 20⁰C, respectively. The temperature of junction B will be

Figure shown two air-filled bulbs connected by a U-tube partly filled with alcohol. What happens to the levels of alcohol in the limbs X and Y when an electric bulb placed midway between the bulbs is lighted?

The rectangular surface of area 8 cm × 4 cm of ablack body at a temperature of 127⁰C emits energy at the rate of E per second. If the length and breadth of the surface are each reduced to half of the initial value and the temperature is raised to 327⁰C, the rate of emission of energy will become

The rates of cooling of two different liquids put inexactly similar calorimeters and kept in identicalsurroundings are the same if

Hot water cools from 60⁰C to 50⁰C in the first 10 min and to 42⁰C in the next 10 min. The temperature of the surrounding is

There are two thin spheres A and B of the samematerial and same thickness. They behave like black bodies. Radius of A is double that of B and both have same temperature T. When A and B are kept in a room of temperature T₀ (< T), the ratio of their rates of cooling is (assume negligible heat exchange between A and B)

Heat is required to change 1 kg of ice at - 20⁰C intostream. Q₁ is the heat needed to warm the ice from -20⁰C to 0⁰C, Q₂ is the heat needed to melt the ice, Q₃is the heat needed to warm the water from 0⁰C to100⁰C and Q₄ is the heat needed to vapourize the water. Then

A piece of metal floats in mercury. The coeficients of volume expansion of the metal and mercury are γ₁ and γ₂ , respectively. If the temperatures of both mercury and the metal are increased by ΔT , the fraction of the volume of the metal submerged inmercury changes by the factor of

Three rods of identical cross-sectional area and madefrom the same metal form the sides of an isoscelestriangle ABC right angled at B. The points A and Bare maintained at temperatures T and  ,respectively, in the steady state. Assuming that only heat conduction takes place, temperature of point C is

When the temperature of a black body increases, itis observed that the wavelength corresponding to maximum energy changes from 0.26 μm to 0.13 μm.The ratio of the emissive powers of the body at therespective temperatures is

A box contains N molecules of a perfect gas attemperature T₁ and pressure P₁. The number ofmolecules in the box is doubled keeping the totalkinetic energy of the gas same as before. If the newpressure is P₂ and temperature T₂, then

The expansion of units mass of a perfect gas atconstant pressure is shown in Fig. Here.

A gas is filled in the cylinder shown in Fig. The twopistons are joined by a string. If the gas is heated,the right piston will

If pressure of a gas contained in a closed vessel inincreased by 0.4% when heated by 1⁰C, the initial temperature must be

Pressure versus temperature graph of an ideal gasof equal number of moles of different volumes isplotted as shown in Fig. Choose the correctalternative.

​A gas is heated at a constant pressure. The fraction of heat supplied used for external work is

A monatomic gas expands at constant pressure onheating. The percentage of heat supplied thatincrease the internal energy of the gas and that isinvolved in the expansion is

The average degrees of freedom per molecule for a gas are 6. The gas performs 25 J of work when it expands at constant pressure. The heat absorbed y gas is

A and B are two isolated spheres kept in closeproximity so that they can exchange energy byradiation. The two spheres have identical physicaldimensions but the surface of A behave like aperfectly black body while the surface of B reflects 20% of all the radiations it receives. They are isolatedfrom all other sources of radiation.