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A Carnot engine has an efficiency of $50\%$ when its source is at a temperature $327^\circ \mathrm{C}$. The temperature of the sink is:
A point mass $m$ is moved in a vertical circle of radius $r$ with the help of a string. The velocity of the mass is $\sqrt{7gr}$ at the lowest point. The tension in the string at the lowest point is:
A ball of mass 0.15 kg is dropped from a height 10 m, strikes the ground, and rebounds to the same height. The magnitude of impulse imparted to the ball is ($g=10 \text{ m/s}^2$) nearly:
Liquid oxygen at $50\text{ K}$ is heated to $300\text{ K}$ at constant pressure of $1\text{ atm}$. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time?
For an adiabatic process, the factor which remains constant is: (all the notations have their usual meaning)
The measurement of an unknown resistance R is to be carried out using a Wheatstone bridge. Two students perform an experiment in two ways. The first student takes R₂ = 10 Ω and R₁ = 5 Ω. The other student takes R₂ = 1000 Ω and R₁ = 500 Ω. In the standard arm, both take R₃ = 5 Ω. Both find R = (R₂/R₁) × R₃ = 10 Ω within errors. Consider the following statements: (a) The errors of measurement of the two students are the same. (b) Errors of measurement do depend on the accuracy with which R₂ and R₁ can be measured. (c) If the student uses large values of R₂ and R₁, the currents through the arms will be feeble. This will make the determination of the null point accurately more difficult. (d) Wheatstone Bridge is a very accurate instrument and has no errors of measurement. Choose the correct option from the given ones:
Two rods, one made of copper and the other made of steel, of the same length and same cross-sectional area are joined together. The thermal conductivity of copper and steel are $385\text{ J s}^{-1}\text{K}^{-1}\text{m}^{-1}$ and $50\text{ J s}^{-1}\text{K}^{-1}\text{m}^{-1}$ respectively. The free ends of copper and steel are held at $100^{\circ}\text{C}$ and $0^{\circ}\text{C}$ respectively. The temperature at the junction is, nearly:
If $\Delta U$ and $\Delta W$ represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true?
A negligibly small current is passed through a wire of length 15 m and uniform cross-section 6.0 × 10⁻⁷ m², and its resistance is measured to be 5.0 Ω. What is the resistivity of the material at the temperature of the experiment?
A thermodynamic system is taken through the cycle $abcda$. The work done by the gas along the path $bc$ is:
A storage battery of emf 8.0 V and internal resistance 0.5 Ω is being charged by a 120 V DC supply using a series resistor of 15.5 Ω. What is the terminal voltage of the battery during charging?
A gas is taken through the cycle $A \rightarrow B \rightarrow C \rightarrow A$, as shown. What is the net work done by the gas?
The current drawn from a 12 V supply with internal resistance 0.5 Ω by the infinite network (shown in the figure) is:
A monoatomic gas at a pressure $P$, having a volume $V$, expands isothermally to a volume $2V$ and then adiabatically to a volume $16V$. The final pressure of the gas is: (Take: $\gamma = \frac{5}{3}$)
An ideal gas undergoes four different processes from the same initial state (figure). Four processes are adiabatic, isothermal, isobaric and isochoric. Out of $1$, $2$, $3$ and $4$, which one is adiabatic?
Two positive ions, each carrying a charge q, are separated by a distance d. If F is the force of repulsion between the ions, the number of electrons missing from each ion will be (e being the charge on an electron):
A gas is taken through the cycle $A \rightarrow B \rightarrow C \rightarrow A$, as shown in the figure. What is the total amount of work done by the gas?
The P-V diagram for an ideal gas in a piston-cylinder assembly undergoing a thermodynamic process is shown in the figure. The process is:
Arrange the following in the order of their resistance: (A) Ammeter of range 0 to 1 A (B) Milli-ammeter of range 0 to 100 mA (C) Micro-ammeter of range 0 to 500 μA (D) Voltmeter of range 0 to 100 V
One mole of an ideal gas from an initial state A undergoes via two processes. It first undergoes isothermal expansion from volume $V$ to $3V$ and then its volume is reduced from $3V$ to $V$ at constant pressure. The correct $P-V$ diagram representing the two processes is -