# Idea of Temperature

## Trending Questions

**Q.**The charge flowing through a resistance R varies with time t as Q=at−bt2, where a and b are positive constants. The total heat produced in R is:

- a3R6b
- a3R3b
- a3R2b
- a3Rb

**Q.**The balancing length for a cell is 560 cm in a potentiometer experiment. When an external resistance of 10 Ω is connected in parallel to the cell, the balancing length changes by 60 cm. If the internal resistance of the cell is N10Ω, where N is an integer, then the value of N is

**Q.**A platinum wire has a resistance of 10Ω at 0∘C and 20Ω at 273∘C. Find the value of temperature coefficient of platinum.

- 1∘273C−1
- 1∘273K−1
- 1∘546K−1
- 1∘546C−1

**Q.**In the arrangement shown in the figure when the switch S2 is open, the galvanometer shows no deflection for l=L2. When the switch S2 is closed, the galvanometer shows no deflection for l=5L12. The internal resistance (r) of 6 V cell, and the emf E of the other battery are respectively

- 3 Ω, 8 V
- 2 Ω, 12 V
- 2 Ω, 24 V
- 3 Ω, 12 V

**Q.**The amount of heat generated in a coil of resistance R due to a charge q passing through it if the current in the coil, decreases down to 0 uniformly during a time internal to is -

- 23q2Rto
- 43q2Rto
- 13q2Rto
- 43qR2to

**Q.**Resistance of a resistor at temperature t oC is Rt=R0(1+αt+βt2), where R0 is the resistance at 0 oC. The temperature coefficient of resistance at temperature t oC is

- (1+αt+βt2)α+2βt
- (α+2βt)
- α+2βt(1+αt+βt2)
- α+2βt2(1+αt+βt2)

**Q.**A wire of length L and 3 identical cells of negligible internal resistances are connected in series. Due to this current, the temperature of the wire is raised by ΔT in a time t. A number N of similar cells is now connected in series with a wire of the same material and cross-section but of length 2L. The temperature of wire is raised by same amount ΔT in the same time t. Find the value of N.

- 4
- 6
- 8
- 2

**Q.**A wire X of half the diameter and half the length as of a wire Y of similar material. The ratio of resistances of X to that of Y is -

- 8:1
- 4:1
- 2:1
- 1:1

**Q.**The same mass of copper is drawn into two wires A and B of radii r and 3r respectively. They are connected in series, and electric current is passed. The ratio of the heat proiduced in A and B is :

- 1:9
- 1:81
- 81:1
- 9:1

**Q.**A 5.0 μF capacitor having a charge of 20 μC is discharged through a wire of resistance of 5.0 Ω. Find the heat dissipated in the wire between 25 μs to 50 μs after the connections are made. (Take, 1/e2=0.135)

- 4.7 μJ
- 3.7 μJ
- 5.7 μJ
- 2.7 μJ

**Q.**Two resistors with temperature coefficient of resistance α1 and α2 have resistance R1 and R2 at 0∘C. The temperature coefficient of the compound resistor consisting of the two resistors connected in parallel

- α1+α22
- 2α1α2α1+α2
- R1α1+R2α2R1+R2
- R1α2+R2α1R1+R2

**Q.**The temperature coefficient of resistance of a conductor varies as α(T)=3T2+2T. If R0 is resistance at T=0 and R is resistance at T, then

- R=R0(6T+2)
- R=2R0(3+2T)
- R=R0(1+T2+T3)
- R=R0(1−T+T2+T3)

**Q.**The charge flowing through a resistance R varies with time as Q=at−bt2, where a and b are positive constants. The total heat produced in R for the time interval t=0 to time when current is zero for the first time is -

- a3R6b
- a3R3b
- a3R2b
- a3Rb

**Q.**The initial connection of the two capacitors are shown below. The heat energy dissipated until the system achieves its steady state is

- CV27
- 3CV25
- 5CV211
- 9CV222

**Q.**Resistance of a resistor at temperature t∘C is Rt=R0(1+at+bt2); where R0 is the resistance at 0∘C. The temperature coefficient of resistance at temperature t∘C is

- (a+2bt)
- (1+at+bt2)a+2bt
- a+2bt(1+at+bt2)
- a+2bt2(1+at+bt2)

**Q.**One of the circuits for the measurement of resistance using potentiometer is as shown. The galvanometer is connected at point A and zero deflection is observed at length PJ=30 cm. In second case the secondary cell is changed and the zero deflection is observed at length PJ=10 cm.The resistance R (in ohm) is?

For 1stcase, take ϵs=10V and r=1 Ω and for 2ndcase, take ϵs=5V and r=2 Ω

**Q.**A wire breaks when subjected to a stress S. If ρ is the density of the material of the wire and g, the acceleration due to gravity, then the length of the wire so that it breaks by its own weight is :

- ρ/gs
- gs/ρ
- s/ρg
- ρgs

**Q.**Compute the greatest length of steel wire that can hang vertically without breaking under its own weight. (Breaking stress of steel wire 7.2 ×108 N/m2, density of steel =7800kg/m3)

**Q.**An elevator cable is to have a maximum stress of 7×107n/m2 to allow for appropriate safety factors. Its maximum upward acceleration is 1.5 m/s2. If the cable has to support the total weight of 2000 kg of a loaded elevator, the area of cross-section of the cable should be

- 3.22 cm2
- 2.38 cm2
- 8.23 cm2
- 0.32 cm2

**Q.**The separation between the plates of a charged parallel-plate capacitor is increased. Which of the following quantities will change?

- Charge on the capacitor
- Potential difference across the capacitor
- Energy density between the plates
- None of these

**Q.**What would be the greatest length of a steel wire, which when fixed at one end can hang freely without breaking (Density of steel = 7800kg/m3 and Breaking stress = $7.8 \times 10^8 N/m^2)

- 1000 m
- 10, 000 m
- 7, 000 m
- 700 m

**Q.**A copper and a steel wire of the same diameter are connected end to end. A deforming force F is applied to this composite wire which causes a total elongation of 1cm. The two wires will have then

- the same stress but different strain
- the same strain but different stress
- the same stress and strain
- different strains and stress

**Q.**A steel wire AB of length 100 cm is fixed rigidly at points A and B in an aluminium frame as shown in the figure If the temperature of the system increases through 100C, then the excess stress produced in the steel wire relative to the aluminium? αμ=22×10−6/0Candαstret=11×10−6/0C young 's modulus of steel is 2×1031Nm−2

- 2.2×105Pa
- 22×1027Pa
- 2.2×102Pa
- 220×102Pa

**Q.**In a mechanical refrigerator, the temperature coils are at a temperature −230C and the compressed gas in condenser has a temperature of 270C. Theoretical coefficient of performance is:

- 10
- 8
- 5
- 6.5

**Q.**The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 1240nm, is incident on it. The band gap for the semiconductor is:

- 2.1eV
- 2.5eV
- 1eV
- 0.7eV

**Q.**For steel, the breaking stress is 6×106N/m2 and the density is 8×103kg/m3. The maximum length of steel wire, which can be suspended without breaking under its own weight is (g=10m/s2)

- 140m
- 120m
- 75m
- 200m

**Q.**In the arrangement shown in figure, when switch S is closed, find the final charge on the 6μF capacitor :

- 12μC
- 24μC
- 32μC
- 48μC

**Q.**A bar weighing 100 N hinged at one end and the end is tied to a vertical string which keeps the bar horizontal. The tension in the string in nearer to

- 500N
- 100N
- 50N
- 10N

**Q.**A platinum wire has a resistance of 10Ω at 0∘C and 20Ω at 273∘C. Find the value of temperature coefficient of platinum.

- 1∘273C−1
- 1∘273K−1
- 1∘546C−1
- 1∘546K−1

**Q.**In an experiment to measure the internal resistance of a cell by a potentiometer, it is found that the balance point is at a length of 2 m when the cell is shunted by a 5 Ω resistance and is at a length of 3 m when the cell is shunted by a 10 Ω resistance, then the internal resistance of the cell is

- 1.5 Ω
- 10 Ω
- 15 Ω
- 1 Ω