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Recent questions tagged physics
Questions
If the temperature of metal sphere increases by $\;\bigtriangleup t\;$ , the fractional change in its moment of inertia is $\;(\alpha \;= Coefficient\; of\; linear \;expansion )$
jeemain
physics
class11
cbse
thermodynamics
thermal-expansion
easy
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 $).
jeemain
physics
class11
cbse
thermodynamics
heat transfer
easy
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
jeemain
physics
class11
cbse
thermodynamics
heat transfer
easy
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 .
jeemain
physics
class11
cbse
thermodynamics
heat transfer
easy
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 ?
jeemain
physics
class11
cbse
thermodynamics
heat transfer
easy
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 ?
jeemain
physics
class11
cbse
thermodynamics
heat transfer
easy
asked
Apr 8, 2014
by
yamini.v
1
answer
Assume that an electric field $\bar {E}=30x^2 \hat i$ exists in space. Then the potential difference $V_A - V_O$ , where $V_O$ is the potential at the origin and $V_A$ the potential at $x = 2$ $m$ is :
jeemain
jeemain-2014
physics
q30
medium
asked
Apr 7, 2014
by
meena.p
1
answer
Two beams, $A$ and $B$, of plane polarized light with mutually perpendicular planes of polarization are seen through a polaroid. From the position when the beam $A$ has maximum intensity (and beam $B$ has zero intensity), a rotation of polaroid through $30^{\circ}$ makes the two beams appear equally bright. If the initial intensities of the two beams are $I_A$ and $I_B$ respectively, then $\large\frac{I_A}{I_B}$ equals :
jeemain
jeemain-2014
physics
q29
medium
asked
Apr 7, 2014
by
meena.p
1
answer
On heating water, bubbles being formed at the bottom of the vessel detatch and rise. Take the bubbles to be spheres of radius $R$ and making a circular contant fo radius $r$ with the bottom of the vessel. If $r << R$ and the surface tension of water is $T$, value of $r$ just before bubbles detatch is : (density of water is $\rho_w$ )
jeemain
jeemain-2014
physics
q28
medium
asked
Apr 7, 2014
by
meena.p
1
answer
When a rubber-band is stretched by a distance $x$, it exerts a restoring force of magnitude $F=ax+bx^2$ where $a$ and $b$ are constants. The work done in stretching the unstretched rubber-band by $L$ is :
jeemain
jeemain-2014
physics
q27
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A block of mass $m$ is placed on a surface with a vertical cross section given by $y=\large\frac{x^3}{6}$. If the coefficient of friction is $0.5$, the maximum height above the ground at which the block can be placed without slipping is :
jeemain
jeemain-2014
physics
q26
medium
asked
Apr 7, 2014
by
meena.p
1
answer
The radiation corresponding to $3 \to 2$ transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magentic field of $3 \times 10^{-4}T$ . If the radius of the largest circular path followed by these electrons is $10.0\; mm$, the work function of the metal is close to :
jeemain
jeemain-2014
physics
q25
medium
asked
Apr 7, 2014
by
meena.p
1
answer
Hydrogen $\bigg( _1H^1\bigg)$, Deuterium $\bigg(_1H^2 \bigg)$, singly ionised Helium $\bigg(_2He^{4}\bigg)^+$ and doubly ionised . Consider an electron transition from $n = 2$ to $n = 1$. If the wave lengths of emitted radiation are $\lambda _1, \lambda_2, \lambda_3\;and \;\lambda_4$ respectively then approximately which one of the following is correct?
jeemain
jeemain-2014
physics
q24
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A green light is incident from the water to the air-water interface at the critical angle $(\theta)$ . Select the correct statement
jeemain
jeemain-2014
physics
q23
medium
asked
Apr 7, 2014
by
meena.p
1
answer
There is a circular tube in a vertical plane. Two liquids which do not mix and of densities $d_1$ and $d_2$ are filled int hetube. Each liquid subtends $90^{\circ}$ angle at centre. Radius joining there interface makes an angle $\alpha$ with vertical. Ratio $\large\frac{d_1}{d_2}$ is
jeemain
jeemain-2014
physics
q22
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A pipe of length $85\;cm$ is closed from one end. Find the number of possible natural oscillations of air column in the pipe whose frequencies lie below $1250\; Hz$. The velocity of sound in air is $340\; m/s$.
jeemain
jeemain-2014
physics
q21
medium
asked
Apr 7, 2014
by
meena.p
1
answer
Three rods of Copper, Brass and Steel are welded together to form a $Y$- shaped structure. Area of cross -section of each rod $= 4 cm^2$. End of copper rod is maintained at $10^{\circ}C$.Lengths of the copper, brass and steel rods are $46, 13 \;and \;12\; cms$ respectively. The rods are thermally insulated from surroundings except at ends. Thermal conductivies of copper, brass and steel are $0.92, 0.26\; and\; 0.12$ CGS units respectively. Rate of heat flow through copper rod is
jeemain
jeemain-2014
physics
q20
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A thin convex lens made from crown glass $\bigg(\mu=\large\frac{3}{2}\bigg)$ has focal length $f.$When it is measured in two different liquids having refractive indices $\large\frac{4}{3}$ and $\large\frac{5}{3}$, it has the focal lengths $f_1$ and $f_2$ respectively. The correct relation between the focal lengths is
jeemain
jeemain-2014
physics
q19
medium
asked
Apr 7, 2014
by
meena.p
1
answer
From a tower of height $H$, a particle is thrown vertically upwards with a speed $u$. The time taken by the particles, to hit the ground, is n times that taken by it to reach the highest point of its path. The relation between $H, u\; and\; n$ is
jeemain
jeemain-2014
physics
q18
medium
asked
Apr 7, 2014
by
meena.p
1
answer
One mole of diatomic ideal gas undergoes a cyclic process $ABC$ as shown in figure. The process $BC$ is adiabatic. The temperatures at $A, B\; and\; C$ are $400 K,800 K\; and\; 600 K$ respectively. Choose the correct statement.
jeemain
jeemain-2014
physics
q17
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A mass $m$ is supported by a massless string wound around a uniform hollow cylinder of mass $m$ and radius $R$. If the string does not slip on the cylinder, with what acceleration will the mass fall on release?
jeemain
jeemain-2014
physics
q16
medium
asked
Apr 7, 2014
by
meena.p
1
answer
In the circuit shown here, the point $C$ is kept connected to point $A$ till the current flowing through the circuit becomes constant. Afterward, suddenly, point $C$ is disconnected from point $A$ and connected to point $B$ at time $t = 0.$ Ratio of the voltage across resistance and the inductor at $t = \large\frac{L}{R}$ will be equal to
jeemain
jeemain-2014
physics
q15
medium
asked
Apr 7, 2014
by
meena.p
1
answer
During the propagation of electromagnetic waves in a medium
jeemain
jeemain-2014
physics
q14
medium
asked
Apr 7, 2014
by
meena.p
1
answer
The forward biased diode connection is
jeemain
jeemain-2014
physics
q13
medium
asked
Apr 7, 2014
by
meena.p
1
answer
The coercivity of a small magnet where the ferromagnet gets demagnetized is $3 \times10^3\;Am^{-1}$. The current required to a passed in a solenoid of length $10\; cm$ and number of turns $100$, so that the magnet gets demagnetized when inside the solenoid, is
jeemain
jeemain-2014
physics
q12
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A particles moves with simple harmonic motion in a straight line. In first ${\tau} {s}$ after starting fromrest it travels a distance $a$, and in next ${\tau} {s}$ in travels $2a$ in same direction, then
jeemain
jeemain-2014
physics
q11
medium
asked
Apr 7, 2014
by
meena.p
1
answer
In a large building, there are $15$ bulbs of $40 \;W$, $5$ bulbs of $100\; W$, $5$ fans of $80\; W$ and 1 heater of $1\; kW$. The voltage of the electric mains is $220\; V$. The minimum capacity of the main fuse of the building will be
jeemain
jeemain-2014
physics
q10
medium
asked
Apr 7, 2014
by
meena.p
1
answer
Four particles, each of mass M and equidistant from each other, move along a circle of radius R under the action of their mutual gravitational attraction. The speed of each particle is
jeemain
jeemain-2014
physics
q9
medium
asked
Apr 7, 2014
by
meena.p
2
answers
A student measured the length of a rod and wrote it as $3.50\; cm$.What instrument did he use to measure it?
jeemain
jeemain-2014
physics
q8
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A parallel plate capacitor is made of two circular plates separated by a distance of $5mm$ and with a dielectric of dielectric constant $2.2$ between them. When the electric field in the dielectric is $ 3 \times 10^4 \;V/m$, the change density of the positive plate will be close to
jeemain
jeemain-2014
physics
q7
medium
asked
Apr 7, 2014
by
meena.p
1
answer
Match List- I (Electromagnetic wave type) with List-II (Its association/application) and select the correct option from the choices given below the lists :
jeemain
jeemain-2014
physics
q6
medium
asked
Apr 7, 2014
by
meena.p
1
answer
An open glass tube is immersed in mercury in such a way that a length of $8\; cm$ extends above the mercury level. The open end of the tube is then closed and sealed and the tube is raised vertically up by additional $46\; cm$. What will be length of the air column above mercury in the tube now? (Atmospheric pressure = $76\; cm$ of Hg)
jeemain
jeemain-2014
physics
q5
medium
asked
Apr 7, 2014
by
meena.p
1
answer
The current voltage relation of diode is given by $I= (e^{1000 V/T } -1)mA$, where the applied voltage V is in volts and the temperature $T$ is in degree kelvin. If a students makes an error measuring $\pm 0.01\;V$ while measuring the current of $5\;mA$ at $300\;K$, what will be error in the value of current in $mA?$
jeemain
jeemain-2014
physics
q4
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A bob of mass $m$ attached to an inextensible string of length $l$ is suspended from a vertical support. The bob rotates in a horizontal circle with an angular speed $\omega\; rad/s$ about the vertical. About the point of suspension
jeemain
jeemain-2014
physics
q3
medium
asked
Apr 7, 2014
by
meena.p
1
answer
A conductor lies along the $z$-axis at $-1.5 \leq z \leq 1.5\;m $ and carries a fixed current of $10.0\;A$ in $-a_{z}$ direction (see figure). For a field $\bar{B}=3.0 \times 10^{-4} e^{-0.2x} \hat a_y\;T$. Find the power required to move the conductor at constant speed to $x = 2.0m, y = 0\;m\;in\; 5 \times 10–3\; s$. Assume parallel motion along the $x$-axis.
jeemain
jeemain-2014
physics
q2
medium
asked
Apr 7, 2014
by
meena.p
1
answer
The pressure that has to be applied to the ends of a steel wire of length $10\; cm$ to keep its length constant when its temperature is raised by $100^{\circ}$ is (For steel, Young's modulus is $2 \times 10^{11} Nm^{-2}$ and coefficient of thermal expansion is $1.1 \times 10^{-5}K^{-4})$
jeemain
jeemain-2014
physics
q1
medium
asked
Apr 7, 2014
by
meena.p
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
cl30184
jeemain
aipmt
physics
cbse
class12
ch2
electrostatic-potential-and-capacitance
capacitors-and-capacitance
q86
difficult
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?
jeemain
physics
experimental-skills-in-physics
difficult
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 ]
jeemain
physics
class11
cbse
thermodynamics
heat transfer
easy
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
jeemain
physics
class11
cbse
thermodynamics
heat-transfer
easy
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
jeemain
physics
class11
specific-heat-capacity
molar-specific-heat
ch13
kinetic-theory-of-gases
easy
asked
Mar 31, 2014
by
yamini.v
1
answer
Helium gas is filled vessel ( having negligible thermal expansion coefficeint ) when heated from 300 K to 600 K . Then the average kinetic energy of atom will be
jeemain
physics
class11
cbse
kinetic-theory-of-gases
easy
kinetic-theory-of-an-ideal-gas
kinetic-energy-of-gas
ch13
asked
Mar 31, 2014
by
yamini.v
1
answer
At what temperature the molecule of nitrogen will have the same rms velocity as the molecule of oxygen at $\;127^{0}C\;$ ?
jeemain
physics
class11
cbse
kinetic-theory-of-gases
medium
kinetic-theory-of-an-ideal-gas
speed-of-molecules
ch13
asked
Mar 31, 2014
by
yamini.v
1
answer
At room temperature , the rms speed of the molecules of a diatomic gas is found to be 1933 m/s . The gas is
jeemain
physics
class11
cbse
kinetic-theory-of-gases
medium
kinetic-theory-of-an-ideal-gas
speed-of-molecules
ch13
asked
Mar 31, 2014
by
yamini.v
1
answer
A gas mixture consists of 2 mol of oxygen and 4 moles of Argon at temperature T . Neglecting all vibrational moles , the total internal energy of the system is
jeemain
physics
kinetic-theory-of-gases
class11
ch13
kinetic-theory-of-an-ideal-gas
kinetic-energy-of-gas
easy
asked
Mar 31, 2014
by
yamini.v
1
answer
If 2 moles of diatomic gas and 1 mole of monoatomic gas are mixed , then ratio of specific heats $\;\large\frac{C_{p}}{C_{v}}\;$ is
jeemain
physics
class11
specific-heat-capacity
molar-specific-heat
kinetic-theory-of-gases
easy
ch13
asked
Mar 27, 2014
by
yamini.v
1
answer
A monoatomic gas expands at constant pressure on heating . The percentage of heat supplied used for external work is
specific-heat-capacity
molar-specific-heat
jeemain
physics
kinetic-theory-of-gases
class11
ch13
medium
asked
Mar 27, 2014
by
yamini.v
1
answer
A gas is heated at constant pressure . The fraction of heat supplied used for external work expressed in terms of the adiabatic index is
specific-heat-capacity
molar-specific-heat
jeemain
physics
kinetic-theory-of-gases
class11
ch13
medium
asked
Mar 27, 2014
by
yamini.v
1
answer
The number of particles in a cubic millimeter of a gas at temperature 273 K and 1.00 atm pressure is
molecular-nature-of-matter
behaviour-of-gases
jeemain
physics
kinetic-theory-of-gases
class11
ch13
ideal-gas-law
easy
asked
Mar 27, 2014
by
yamini.v
1
answer
A closed vessel contains 8 g of oxygen and 7 g of nitrogen . The total pressure is 10 atm at a given temperature . If now oxygen is absorbed by introducing a suitable absorbent , the pressure of the remaining gas is atm will be
medium
daltons-law
jeemain
physics
kinetic-theory-of-gases
class11
ch13
pressure-of-an-ideal-gas
behaviour-of-gases
ideal-gas-law
asked
Mar 27, 2014
by
yamini.v
1
answer
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