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The two ends of a metal rod are maintained at temperatures $100 ^\circ\text{C}$ and $110 ^\circ\text{C}$. The rate of heat flow in the rod is found to be $4.0 \text{ J/s}$. If the ends are maintained at temperatures $200 ^\circ\text{C}$ and $210 ^\circ\text{C}$, the rate of heat flow will be:
On observing light from three different stars $P$, $Q$, and $R$, it was found that the intensity of the violet colour is maximum in the spectrum of $P$, the intensity of the green colour is maximum in the spectrum of $R$ and the intensity of the red colour is maximum in the spectrum of $Q$. If $T_P$, $T_Q$, and $T_R$ are the respective absolute temperatures of $P$, $Q$, and $R$, then it can be concluded from the above observations that:
A black body is at $727^\circ\text{C}$. The rate at which it emits energy is proportional to:
Assuming the sun to have a spherical outer surface of radius $r$, radiating like a black body at temperature $t^\circ \text{C}$, the power received by a unit surface of the earth (normal to the incident rays) at a distance $R$ from the centre of the sun will be: (where $\sigma$ is Stefan's constant)
If the cold junction of a thermocouple is kept at $0^\circ\text{C}$ and the hot junction is kept at $T^\circ\text{C}$, then the relation between neutral temperature ($T_n$) and temperature of inversion ($T_i$) is:
A $40 \text{ \mu F}$ capacitor is connected to a $200 \text{ V}$, $50 \text{ Hz}$ ac supply. The rms value of the current in the circuit is, nearly :
An object kept in a large room having an air temperature of $25^\circ \text{C}$ takes $12 \text{ min}$ to cool from $80^\circ \text{C}$ to $70^\circ \text{C}$. The time taken to cool for the same object from $70^\circ \text{C}$ to $60^\circ \text{C}$ would be nearly:
A deep rectangular pond of surface area $A$, containing water (density = $\rho$, specific heat capacity = $s$), is located in a region where the outside air temperature is at a steady value of $-26^\circ\text{C}$. The thickness of the ice layer in this pond at a certain instant is $x$. Taking the thermal conductivity of ice as $k$, and its specific latent heat of fusion as $L$, the rate of increase of the thickness of the ice layer, at this instant, would be given by:
The coefficients of linear expansion of brass and steel rods are $\alpha_1$ and $\alpha_2$, lengths of brass and steel rods are $l_1$ and $l_2$ respectively. If $(l_2 - l_1)$ is maintained the same at all temperatures, which one of the following relations holds good?
Which amine gives the carbylamine test?
Two metal wires of identical dimensions are connected in series. If $\sigma_1$ and $\sigma_2$ are the conductivities of the metal wires respectively, the effective conductivity of the combination is:
A metal wire has mass $(0.4 \pm 0.002)$ g, radius $(0.3 \pm 0.001)$ mm and length $(5 \pm 0.02)$ cm. The maximum possible percentage error in the measurement of density will nearly be
The net magnetic flux through any closed surface is
A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat $Q$ in time $t$. The metallic rod is melted and the material is formed into a rod of half the radius of the original rod. What is the amount of heat conducted by the new rod when placed in thermal contact with the two reservoirs in time $t$?
Sucrose on hydrolysis gives:
A cup of coffee cools from $90^{\circ}\text{C}$ to $80^{\circ}\text{C}$ in $t$ minutes, when the room temperature is $20^{\circ}\text{C}$. The time taken by a similar cup of coffee to cool from $80^{\circ}\text{C}$ to $60^{\circ}\text{C}$ at room temperature same at $20^{\circ}\text{C}$ is:
Which of the following metal ions activates many enzymes participating in the oxidation of glucose to produce ATP and with Na it is also responsible for the transmission of nerve signals:
A sample of $0.1 \text{ g}$ of water at $100^{\circ}\text{C}$ and normal pressure ($1.013 \times 10^5 \text{ N m}^{-2}$) requires $54 \text{ cal}$ of heat energy to convert it into steam at $100^{\circ}\text{C}$. If the volume of the steam produced is $167.1 \text{ cc}$, then the change in internal energy of the sample will be:
Thermodynamic processes are indicated in the following diagram. Match the following: Column I P. Process I Q. Process II R. Process III S. Process IV Column II a. Adiabatic b. Isobaric c. Isochoric d. Isothermal
A block of mass 10 kg is in contact against the inner wall of a hollow cylindrical drum of radius 1 m. The coefficient of friction between the block and the inner wall of the cylinder is 0.1. The minimum angular velocity needed for the cylinder to keep the block stationary when the cylinder is vertical and rotating about its axis, will be : ($g = 10 \text{ m/s}^2$)