Recent questions in Physics

If $Y_{Steel}=2\times 10^{11}N/m^2$ ,what force must be applied to steel rod of $l=2m$ and $r=2mm$ to stretch it by 1mm

asked May 7, 2014 by sreemathi.v

1 answer

Among rubber and steel which is more elastic

asked May 7, 2014 by sreemathi.v

1 answer

Each side of a cube is decreased by 2% when a pressure of $3\times 10^6N/m^2$ is applied.What is bulk modulus of cube.

asked May 7, 2014 by sreemathi.v

1 answer

A 50KN force is applied on a table,the length of four legs of table is 2m each and of radius 5cm.If young modulus of material of table is $5\times 10^{10}N/m^2$.Find the decrease in length in a leg of table.

asked May 7, 2014 by sreemathi.v

1 answer

A steel rod of r=30mm and length 3m.A 50 KN force is applied along its length.Calculate the change in length is $Y=2\times 10^{11}N/m^2$

asked May 7, 2014 by sreemathi.v

1 answer

A steel wire of 8m in length is stretched by 1mm of cross sectional area $2mmm^2$ .If young modulus of steel is $2\times 10^{11}N/m^2$.What is elastic potential energy?

asked May 7, 2014 by sreemathi.v

1 answer

A 3cm cube has its upper face displaced by 0.1cm by a tangential force.If modulus of rigidity of material is $5\times 10^4N/m^2$.Find the force

asked May 7, 2014 by sreemathi.v

1 answer

If 5litre of ideal gas is compressed isothermally at 800mm Hg to 2 litre.Find its stress?

asked May 7, 2014 by sreemathi.v

1 answer

If we increases the pressure by 20atm on a sphere which is made up of material of bulkmodulus $5.2\times 10^{10}N/m^2$,what is change in volume percentage?

asked May 7, 2014 by sreemathi.v

1 answer

Two wires of same material have radius in the ratio 2 : 1 and length in the ratio 1 : 2.If equal force is applied on them then ratio of stress is

asked May 7, 2014 by sreemathi.v

1 answer

A steel wire of l=15m and r=1mm is stretched by a unknown force F.If young modulus of steel wire is $2.4\times 10^{11}N/m^2$ and change in length is $5\times 10^{-2}mm$

asked May 7, 2014 by sreemathi.v

1 answer

Temperature of $4 mol$ of an ideal gas occupying $5 dm^3$ at $3.32\; bar \; (R= 0.083\;bar \;dm^3 K)$

asked May 2, 2014 by meena.p

1 answer

$4g$ of $O_2$ gas has pressure $P_0$ ad temperature $T_o$ i a vessel . On keeping the Sample at $50^{\circ}\;C$ higher temperature, $1g$ gas is given ad to maintain the original pressure $P_0$ . Then $T_0=?$

asked May 2, 2014 by meena.p

1 answer

The r ms speed of the molecules of a ideal gas which is at a pressure $10^5 \;m^{-2}$ & density $45\;kgm^{-3}$ is _________

asked May 2, 2014 by meena.p

1 answer

Boltzmann curve is given below :

asked May 2, 2014 by meena.p

1 answer

The reason why $Cp$ is greater than $Cv$ is _______

asked May 2, 2014 by meena.p

1 answer

The graph of PV v/s T is plotted for $Co_2,H_2$ and $N_2$ samples of equal masses Then the correct statement is

asked May 2, 2014 by meena.p

1 answer

Which one of the graphs below best illustrates the relationship between internal energy U and temperature T of the gas in K ?

asked Apr 22, 2014 by yamini.v

1 answer

$\;C_{p}\;$ and $\;C_{v}\;$ denote the molar specific heat capacities of a gas at constant pressure and constant volume respectively . Then

asked Apr 22, 2014 by yamini.v

1 answer

The refractive indices of flint glass for red and violet light are 1.613 and 1.632 respectively. Find the angular dispersion produced by a thin prism of flint glass having refracting angle $15 ^{\circ}$

asked Apr 19, 2014 by balaji.thirumalai

1 answer

In a Young's Double Slit experiment, the width of one of the two slits is double the other. If the amplitude of light coming from a slit is proportional to the width, find the ratio of the maximum to minimum intensity in the interference pattern.

asked Apr 19, 2014 by balaji.thirumalai

1 answer

Two monochromatic coherent sources of wavelength 5000 A are placed along line normal to screen as shown. Find the order of central bright fringe if $d = 0.5mm$ and $D = 1m$

asked Apr 19, 2014 by balaji.thirumalai

1 answer

An ideal gas initially at a state $\;(P_{1},V_{1})\;$ is allowed to expand isothermally to a state $\;(P_{2},V_{2})\;$ . Then the gas is compressed adiabatically to its initial volume $\;V_{1}\;$ . Let the final pressure be $\;p_{3}\;$ and the workdone by the gas be W , Then

asked Apr 9, 2014 by yamini.v

1 answer

A sample of an ideal gas is taken through the process ABCA shown . It rejects 50 J of heat during part AB , does not absorb or reflect heat during BC and accepts 70 J of heat during CA . Forty joules of work is done on the gas during the part BC . The internal energies at B and C respectively will be $\;(u_{A} =1500\;J)$

asked Apr 9, 2014 by yamini.v

1 answer

Logarithms of readings of pressure and volume from ideal gas were plotted on a graph as shown . By measuring the gradient , it can be shown that the gas may be

asked Apr 9, 2014 by yamini.v

1 answer

An ideal gas is filled in a closed rigid and thermally insulated container . A coil of 100 oms resistor carrying a current of 1 A for 5 minutes supplies heat to the gas . The change in the internal energy of the gas is

asked Apr 9, 2014 by yamini.v

1 answer

An ideal gas is taken through the cycle $\;A \to B \to C \to A \;$ as shown in the figure . If the net heat supplied to the gas in the cycle is 5 J , the work done by the gas is the process $\;C \to A\;$ is

asked Apr 9, 2014 by yamini.v

1 answer

Starting from the same initial conditions , an ideal gas expands from volume $\;V_{1}\;$ to $\;V_{2}\;$ in three different ways . The work done by the gas is $\;W_{1}\;$ if the process is purely isothermal , $\;W_{2}\;$ if purely isobaric and $\;W_{3}\;$ if purely adiabatic . Then :

asked Apr 9, 2014 by yamini.v

1 answer

A thermodynamics ideal gas , initially at temperature $\;T_{1}\;$ ia enclosed in a cylinder fitted with a friction less piston . The gas is allowed to expand adiabatically to a temperature $\;T_{2}\;$ by releasing the piston suddenly . If $\;L_{1}\;$ and $\;L_{2}\;$ are the lengths of gas column before and after expansion respectively , then $\;\large\frac{T_{1}}{T_{2}}\;$ is given by

asked Apr 9, 2014 by yamini.v

1 answer

A thermodynamic process , the pressures and volumes corresponding to some points in the figure are $\;P_{A} = 3 \times 10^{4}\;pa \;,V_{A} = 2 \times 10^{-3} \;m^3\;$ . $\;P_{B}=8 \times 10^{4}\;pa\;V_{D} = 5 \times 10^{-3}\;m^3\;$. In the process AB , 600 J of heat and in the process BC , 200 J of heat is added to the system . The change in internal energy in process AC would be

asked Apr 9, 2014 by yamini.v

1 answer

Volume $\;V_{S}\;$ Temperature graph of two moles of helium gas is show in figure . The ratio of heat absorbed and the work done by the gas in process 1 - 2 is

asked Apr 9, 2014 by yamini.v

1 answer

Which type of ideal gas will have the largest value for C$_P$-C$_V$?

asked Apr 8, 2014 by yamini.v

1 answer

A copper disc at $\;0^{0}C\;$ has a diameter of 50 cm and a hole is cut in the center with a diameter 5 cm . The diameter of the hole at $\;100^{0}C\;$ will be $\;(\alpha = 0.00016/^{0}C)\;$

asked Apr 8, 2014 by yamini.v

1 answer

A composite bar of length $\;(l_{1} + l_{2})\;$ is made from two bars of length $\;l_{1}\;$ and $\;l_{2}\;$ . Their coefficients of linear expansion $\;\alpha_{1}\;$ and $\;\alpha_{2}\;$ respectively . The effective linear coefficient of composite bar

asked Apr 8, 2014 by yamini.v

1 answer

When a block of iron floats in mercury at $\;0^{0}C\;$ , a fraction $\;K_{1}\;$ of its volume is submerged. While at the temperature $\;60^{0}C\;$ , a fraction $\;K_{2}\;$ is seen submerged . If the coefficient of volume expansion of iron is $\;r_{Fe}\;$ and that of mercury is $\;r_{Hg}\;$ , then the ratio $\;\large\frac{K_{1}}{K_{2}}\;$ can be expanded as

asked Apr 8, 2014 by yamini.v

1 answer

The apparent expansion of a liquid when heated in a copper vessel is C and when heated in a silver vessel is S . If A is coefficient of linear expansion of silver is

asked Apr 8, 2014 by yamini.v

1 answer

$\;l_{1}\;$ and $\;l_{2}\;$ are the lengths of two rods at $\;0^{0}C\;$ and have coefficients of linear expansion $\;\alpha_{1}\;$ and $\;\alpha_{2}\;$ respectively . If the difference between the lengths X is the same at all temperatures then $\;l_{1}\;$ is

asked Apr 8, 2014 by yamini.v

1 answer

A wire of length 60 cm is bent into a circle with a gap of 1 cm at its ends . On heating by by $\;100^{0}C\;$ , If the length of the gap increases to 1.02 cm , $\;\alpha\;$ of the material of the wire is

asked Apr 8, 2014 by yamini.v

1 answer

The brass scale of a barometer is correct at $\;0^{0}C\;$ and it reads 755 mm at $\;25^{0}C\;$ , Its reading at $\;0^{0}C\;$ is $\;r_{mercury} = 0.00018/^{0}C\;,r_{brass} =0.00021/^{0}C$

asked Apr 8, 2014 by yamini.v

1 answer

If the temperature of metal sphere increases by $\;\bigtriangleup t\;$ , the fractional change in its moment of inertia is $\;(\alpha \;= Coefficient\; of\; linear \;expansion )$

asked Apr 8, 2014 by yamini.v

1 answer

The wavelength $\;\lambda_{m}\;$ of maximum intensity of emission of solar radiation is $\;\lambda_{m}=14\; \mu m\;$. The surface temperatures of sun and moon are (given $ b= 2.898 \times 10^{-3} \; metre/Kelvin $).

asked Apr 8, 2014 by yamini.v

1 answer

A metal ball having surface area of $\;2 \times 10^{-2}\;m^2\;$ and at 900 K is kept in an enclosure at 300 K . If the surface emissivity of metal is 0.4 , find the rate of which heat is lost by the ball

asked Apr 8, 2014 by yamini.v

1 answer

A steel rod of length 20 cm and cross sectional area 3 $cm^{2}$ is heated at one end to $\;300^{0}C\;$ and the other end is in ice . Assuming no loss of heat , the mass of ice that melts in 10 minutes if $\;K_{steel} = 0.16 \;C.G.S\;$ units .

asked Apr 8, 2014 by yamini.v

1 answer

The temperature of a solid falls from $\;77^{0}C\;$ to $\;73^{0}C\;$ in 3 minutes and $\;73^{0}C\;$ to $\;69^{0}C\;$ in 4 minutes . What is the room temperature ?

asked Apr 8, 2014 by yamini.v

1 answer

The temperature of a solid falls from $\;72^{0}C\;$ to $\;60^{0}C\;$ in 10 minutes . How much time will it take to cool from $\;60^{0}C\;$ to $\;52^{0}C\;$ if the temperature of surroundings is $\;36^{0}C\;$ c ?

asked Apr 8, 2014 by yamini.v

1 answer

Figure shows a capacitor made of two circular plates each of radius $12\: cm$, and separated by $5\: cm$. The capacitor is being charged by an external source. The charging current is constant and equal to $0.15\: A$. The rate of change in potential difference between the plates is

asked Apr 3, 2014 by balaji.thirumalai

1 answer

The main scale of a vernier calipers reads in millimeter and its vernier scale is divided into 10 divisions which coincide with 9 divisions of the main scale. When the two jaws of the instrument touch each other the seventh division of the vernier scale coincide with a scale division and the zero of the vernier lies to the right of the zero of the main scale. Furthermore, when the cylinder is tightly placed along its length between the two jaws, the zero of the vernier sale lies slightly to the left of 3.2 cm; and the fourth vernier division coincides with a scale division. What will the measured length of the cylinder be?

asked Apr 2, 2014 by balaji.thirumalai

1 answer

A copper rod AB of length 100 cm is fixed with a steel rod BC of length 20 cm at B . If the ends A and C are maintained at temperature $\;100^{0}C\;$ and $\;0^{0}C\;$ , then the temperature of the function B is : [thermal conductivities of copper and steel are 0.9 and 0.18 CGS units respectively ]

asked Mar 31, 2014 by yamini.v

1 answer

A cylinder of radius r and thermal conductivity $\;K_{1}\;$ is surrounded by cylindrical shell of inner radius r and outer radius 2r and thermal conductivity $\;K_{2}\;$ . The effective thermal conductivity when ends of combined system $\;t_{1}\;$ and $\;t_{2}\;$ under steady state is

asked Mar 31, 2014 by yamini.v

1 answer

For hydrogen gas $\;C_{p}-C_{v} =a\;$ and for oxygen $\;C_{p}-C_{v}=b\;$ . Then the relation between a and b is given by

asked Mar 31, 2014 by yamini.v

1 answer

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