Thermal properties of matter practice · Easy

Option C (Only utensil will shine) is correct because the utensil, being black, will emit radiation due to its temperature, while the carving, being part of the utensil, will not independently shine.

Option A (Coefficient of cubical expansion of liquid must be greater than that of bulb material) is correct because for a thermometer to function properly, the liquid must expand more than the bulb material when heated, allowing the liquid to rise in the tube.

Option C ($327^\circ C$) is correct because it is calculated using Charles's Law, relating volume and temperature at constant pressure.

Option B (3 s) is correct because when in parallel, the effective area doubles, leading to a fourfold increase in heat transfer rate and a quarter of the time.

Option A ($1425 \mathrm{~W}$) is correct because it is the radiation power calculated using Stefan-Boltzmann law with the given temperature, radius, and emissivity.

Option B (In cool air near the bottom and hot air out near the roof) is correct because hot air rises and exits through the top windows, while cool air enters through the bottom windows, creating a natural convection current.

Option B ($\frac{2 \sigma_1 \sigma_2}{\sigma_1+\sigma_2}$) is correct because the effective conductivity is derived from the series combination of resistances.

Option B ($40^\circ C$) is correct because it is calculated using linear interpolation based on the resistance values at different temperatures.

Option C ($5 \times {10^{ - 5}}/{\,^0}C$) is correct because it is calculated using the formula for the coefficient of volume expansion based on the change in height of the liquid column.

Option A (If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion) is correct because liquids generally expand more than solids due to weaker intermolecular forces.

Option C (3.6) is correct because it is the change in volume calculated using the coefficient of linear expansion and the initial volume.

Option B ($5.28 \times {10^8}\,Pa$) is correct because it is calculated using the bulk modulus and the change in temperature to find the change in pressure.

Option D ($1 \times {10^{ - 5}}/{}^ \circ C$) is correct because the coefficient of superficial expansion is approximately twice the coefficient of linear expansion.

Option C (Pyrometer) is correct because pyrometers are used to measure high temperatures, such as that of the sun, by detecting thermal radiation.

Option B (${140^\circ }$) is correct because it is calculated using the relationship between two hypothetical temperature scales.

Option B ($57^\circ C$) is correct because the temperature on the Celsius scale is calculated using the formula relating the faulty thermometer reading to the Celsius scale, accounting for the shifted fixed points.

Option C ($\frac{1}{{300}}/{\,^0}C$) is correct because it is calculated using the formula for the volume coefficient of a gas.

Option B (The line intercepts the positive $y$-axis) is correct because the relationship between Celsius and Fahrenheit is $F = \frac{{9}}{{5}}C + 32$, which is a linear equation with a y-intercept of 32.

Option A is correct. Compensating leads are used in platinum resistance thermometers to eliminate stem corrections, which account for the temperature variation along the length of the leads.

Option C (Same for both the bars) is correct because the change in length depends on the original length, the coefficient of linear expansion, and the change in temperature, none of which depend on the diameter.

Option D ($-21^{\circ} \mathrm{C}$) is correct because the temperature is calculated using the linear relationship between resistance and temperature in a resistance thermometer.

Option A is correct. The coefficient of cubical expansion for an anisotropic substance is the sum of the coefficients of linear expansion along the three axes: ${\alpha_1} + {\alpha_2} + {\alpha_3}$.

Option D (${4^\circ }C$) is correct because water has maximum density at ${4^\circ }C$, so the bottom of the lake will be at this temperature.

Option C (Temperature) is correct because the color of a star is directly related to its surface temperature, following Wien's displacement law.

Option B (1.6 units) is correct because the effective conductivity of rods in series is calculated using the formula 1/K_eff = (1/K1 + 1/K2 + 1/K3)/3, which simplifies to K_eff = 3 / (1/1 + 1/2 + 1/3) = 1.6.

Option D ($25^\circ C$) is correct because the temperature is calculated using the ratio of the length of the mercury thread above the lower fixed point to the total length between the fixed points.

Option C (Both 1 and 2) is correct because 0.8 k Cal is equivalent to 800 Cal, and both represent the heat required to melt 10 g of ice at 0°C.

Option D ($\frac{{16}}{{22}} \times 100$) is correct because the temperature is calculated using the ratio of the length difference to the total length difference between the steam and ice points.

Option C (-460 °F) is correct because absolute zero (0 K or -273.15 °C) corresponds to approximately -459.67 °F, which is rounded to -460 °F.

Option D (Boiling Point) is correct because the boiling point is defined as the temperature at which the vapor pressure of a liquid equals the external pressure.