a) Current is given as I = V/R from the Ohm’s law Therefore, I = 1A But, I = ne Avd vd = I/neA When the values for the above parameters are substituted, vd = 1/1.6 × 10-4 m/s The KE = (KE of one...
a) Consider the circuit in the figure. How much energy is absorbed by electrons from the initial state of no current to the state of drift velocity? b) Electrons give up energy at the rate of RI2 per second to the thermal energy. What time scale would one associate with energy in problem a) n = no of electron/volume = 1029/m3, length of circuit = 10 cm, cross-section = A = 1mm2
read more
‘ coalesce to form a large drop of radius ‘ 
and volume ‘ 
. If ‘ 
is the surface tension then energy
is released.
is released.
is absorbed.
and 6 beat/s with a fork of frequency 
. The frequency of the note is
are connected as shown in the figure. The ratio of equivalent capacitance between 
and 
and the equivalent capacitance between 
and 
is
is illuminated with light of energy 
?
‘ at rest. After collision, their final velocities are V’ and 
respectively. The value of 
, with time period 
. If force is changed to 
, it executes S.H.M. with time period 
. Now both the forces act simultaneously in the same direction on the same body. New periodic time is
‘ at a pressure ‘ 
. The mass of each molecule is ‘ 
is the Boltzmann’s constant, then the density of gas is given by expression
. The compressibility of water is 
and density of water is 
. At the bottom of the ocean, the fractional compression of water will be 
, then the specific heat at constant pressure 
, specific heat at constant volume 
and corresponding molecule are respectively
, monoatomic.
, polyatomic.
, non-rigid diatomic.
and weight ‘ 
. One end of the wire is attached rigidly to a point in the roof and weight ‘ 
is suspended from its lower end. If ‘ 
is the cross-sectional area of the wire then the stress in the wire at a height 
from its lower end is
‘. The frequency of oscillation for the S.H.M. along the vertical line is [ 
Young’s modulus of material of the wire ]![\frac{1}{2 \pi}\left[\frac{\mathrm{YAL}}{\mathrm{m}}\right]^{\frac{1}{2}}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-f3925ead959d4f80e07f99802608a95a_l3.png "Rendered by QuickLaTeX.com")
![\frac{1}{2 \pi}\left[\frac{\mathrm{YA}}{\mathrm{mL}}\right]^{\frac{1}{2}}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-5b0a91f33eeb0af7f68b0f0b5612fc04_l3.png "Rendered by QuickLaTeX.com")
![\frac{1}{2 \pi}\left[\frac{\mathrm{mA}}{\mathrm{YL}}\right]^{\frac{1}{2}}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-03f502b7ace2644cbea7275b6e92f850_l3.png "Rendered by QuickLaTeX.com")
![\frac{1}{2 \pi}\left[\frac{\mathrm{YL}}{\mathrm{mA}}\right]^{\frac{1}{2}}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-bc772f47ba021ba390af8b01ac204fb0_l3.png "Rendered by QuickLaTeX.com")
‘ is moving along a circle of radius ‘ 
and to move it along the circle of radius ‘ 
, required change in the centripetal force of the body is
‘. If the height of antenna is doubled, the range covered would become
‘. The electric field intensity due to uniformly charged infinite thin plane sheet is ‘ 
‘. The relation between 
‘ and ‘ 
‘ and density ‘ 
. The dimensions of 
are![\left[\mathrm{L}^{-1 / 2} \mathrm{M}^{3 / 2} \mathrm{~T}^{-2}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-d0e831cace6d7fb698114df4b7d45d13_l3.png "Rendered by QuickLaTeX.com")
![\left[\mathrm{L}^{-1 / 2} \mathrm{M}^{1 / 2} \mathrm{~T}^{-2}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-ca1924b4df824bd3aef6e1f25d91c1cf_l3.png "Rendered by QuickLaTeX.com")
![\left[\mathrm{L}^{-1} \mathrm{M}^{3 / 2} \mathrm{~T}^{-2}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-3c203a52dfdc89b96eab16074bfa6721_l3.png "Rendered by QuickLaTeX.com")
![\left[\mathrm{L}^{-1} \mathrm{M}^{1 / 2} \mathrm{~T}^{-2}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-8d414b1c70e8f1f0cecdb8869f66c412_l3.png "Rendered by QuickLaTeX.com")
then total kinetic energy of the disc is
in an orbit of radius 
. The magnetic moment of the revolving electron is
when on the surface of the earth . The mass is then taken on to a height of 
above earth’s surface and again suspended from the same spring. At this altitude the extension of the spring is 
(Radius of earth 
)
‘ and the stopping potential is ‘ 
‘. The wavelength of the incident radiation is
is also suspended, the period of oscillation will now be
The of curvature of its convex surface is R. Its focal length:
and 
are the wavelengths of the first members of the Lyman and Paschen series respectively, then 
is:
. The number of turns of the solenoid is 500 per metre. The magnetization of the material is nearly.
force due to the weight of the water. The surface tension of water is 
. The inner diameter of the capillary tube is nearly 
, the graph of capacitive reactance 
with frequency ( 
) of the source of alternating signal is
‘. The magnetic field is increased four times. But the proton is constrained to move in the path of same radius. The kinetic energy will increase
Another identical ring is gently placed on it so that their centres coincide. If both the rings are rotating about the same axis then loss is kinetic energy is
acts on a particle in 
direction, where 
to 
.
and its pole strength is 
. The magnetic moment, if it is bent in the form of a semicircle is 
. Its angular momentum is 
. The centripetal force acting on the particle is.
and 
with 
placed in air is given by
resistance in the right gap at a point which divides the bridge wire in the ratio 
. If the length of the resistance wire is 
, then the length of 
of the resistance wire is: 
, then the angle of incidence is nearly equal to: 
capacitor is connected to a 
ac supply. The rms value of the current in the circuit is, nearly: 
in an electric field of 
has a mobility in 
of : 
. With the introduction of a dielectric medium, the capacitance becomes 
. The permittivity of the medium is : 
The permeability of the material of the rod is : 
) 
![\left[\sin ^{-1}\left(\frac{1}{1.5}\right)=41.8^{\circ}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-0caec26c6644af9c6eadbc41ca73eb61_l3.png "Rendered by QuickLaTeX.com")
.
.
‘ will respectively be
is connected across the terminal of a cell of e.m.f. ‘ 
‘ the current is ‘ 
‘. When the resistance is changed to 
‘ the current is ‘ 
‘. The internal resistance of the cell is
![\left[L^{2} M^{1} T^{-1}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-e3ae8151d351e21d072dc99a517680a5_l3.png "Rendered by QuickLaTeX.com")
![\left[L^{2} M^{2} T^{-2}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-570bf7fd6b73030ec948ef99c8b75448_l3.png "Rendered by QuickLaTeX.com")
![\left[L^{2} M^{1} T^{1}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-8a2e9f8d186a5b9fceddc341575a2dfb_l3.png "Rendered by QuickLaTeX.com")
![\left[L^{2} M^{1} T^{-2}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-6d349a07b4098874e03d0238509c1b23_l3.png "Rendered by QuickLaTeX.com")
, when mass of 
is attached to the lower end. Energy gained by the wire is (Take 
)
‘. The respective forces exerted by water on the bases are ‘ 
and respective weights are 
. Then
and 
. The resonating length of the air column in its fundamental mode will be (velocity of sound in air 
from the centre of magnet is
‘. The magnetic induction at the midway between them is 
permeability of free space)
along the direction of 
is
‘ at potential 
‘. The charge on capacitor is increased to ‘ 
‘ so that its potential increases to 
, then the difference between final and initial energy stored in capacitor is
refractive index of oil and angle made by the object at the aperture = 
)
weight is suspended from a weightless spring and it has period ‘ 
. If now ‘ 
weight is suspended from the same spring, the new period will be
and a length of 
. If the horizontal circle traced by the bob has a diameter of 
, then the tension in the string would be nearly 
and 
respectively. The distance between two coherent sources is
![\left[L^{-1} M^{0} T^{0} I^{1}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-61bc00b014420d451f210b1b6d369577_l3.png "Rendered by QuickLaTeX.com")
![\left[L^{-1} M^{0} T^{0} I^{-1}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-c460b6b0a8d363b4b9c32706e423f306_l3.png "Rendered by QuickLaTeX.com")
![\left[L^{-1} M^{1} T^{1} I^{-1}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-9ab8d27e17f1706b0fe994dd5197b794_l3.png "Rendered by QuickLaTeX.com")
and 
. The number of beats produced per minute by these two waves is
, the diameter of the tenth orbit is
‘ is in unison with a tuning fork of frequency’n’. When the vibrating length of the wire is reduced to ‘ 
‘, it produces ‘ 
. The distance travelled by it between 1 st and 2 nd second of its motion is (A = amplitude of S. H. M.)
‘ is enclosed by a Gaussian spherical surface of radius ‘R’. If, now, radius of the spherical surface is doubled the outward electric flux will
when the body is at 
above the temperature of surroundings. When the body is at 
above the temperature of surroundings, its rate of cooling will be
, and 
, respectively and that of moon is 
and 
respectively. The distance between the centre of earth and that of moon is ‘D’ . The minimum speed required for a body (mass ‘m’) to project from a point midway between their centres to escape to infinity is
, the bob of simple pendulum of length ‘L’ is released then its linear displacement at time ‘t’ is
‘ after time ‘t’. If the same point source is placed in the medium of refractive index ‘ 
is
, its rotational kinetic energy will be increased by
Radius of the earth)
‘ must be
, the height of 
tower should be (Radius of earth, 
)
and 
are perpendicular to each other then the magnitude of their vector product is 
,
‘ balls per second. If ‘ 
and then moves away from ‘ 
![\geq\left[\frac{10 g h}{7}\right]^{1 / 2}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-90f667f0759902947f521ac966f472fc_l3.png "Rendered by QuickLaTeX.com")
and 
respectively, what is the maximum permissible error in the density of the material ?
and water has refractive index 
If the speed of light in glass is 
, then the speed of light in water will be
The extension in the string is ‘ 
. If the string is extended by 
, then the speed of wave along the string will be nearly (Hooke’s law is obeyed)
D. 
is connected to a battery of 
with a resistance of 
in series. The deflection obtained is 30 divisions. To reduce this deflection by 10 divisions the additional resistance required to be connected in series is
When the surface is illuminated by monochromatic light of frequency 
, the stopping potential is 
. the threshold frequency for photoelectric emission is:
. Unknown resistance ‘ 
in right gap, null point divides the wire in the ratio 
. Find the current drawn from the battery of 
having negligible resistance.
magnetic susceptibility)
‘ and ‘ 
‘ respectively. The ratio of the mass of 
to that of 
is
![\left[\frac{\mathrm{r}_{2}}{\mathrm{r}_{1}}\right]^{2}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-8576e94466b638e76d49f6a15d3e2940_l3.png "Rendered by QuickLaTeX.com")
![\left[\frac{\mathrm{r}_{1}}{\mathrm{r}_{2}}\right]^{2}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-508e81114cccf8287500c32565603618_l3.png "Rendered by QuickLaTeX.com")
‘ is incident on photosensitive surface, the stopping potential is ‘ 
‘ is incident on same surface, the stopping potential is 
. Threshold wavelength for the surface is
It reduces to 
then ‘t’ in second is
is ‘ 
‘. The work done in increasing it from 
will be
bright band and 
bright band. Wavelength of light used is 
. The path difference between PA and QA is
is connected to a battery of emf 
with 
resistance in series. A full scale deflection of 20 divisions is obtained in the galvanometer. To reduce the deflection to 10 divisions, the resistance in series required is
‘, then potential difference of the other capacitor will become
to 
to 
to 
to 
maximum electron density of ionosphere, 
acceleration due to gravity)
equal to 
voltage gain without feedback, 
feedback factor )
and the separation between the plates is ‘ 
‘, ‘ 
‘ and ‘ 3 d’ respectively. The equivalent capacity of combination is 
absolute permittivity of free space)
at point 
at point 
‘, the de-Broglie wavelength associated with it will be (Assume that wavelength is determined at low voltage)
B) 
ampere flows through the primary coil of the transformer. The coefficient of mutual inductance between primary and secondary coil is 1 henry. The peak e.m.f. induced in secondary coil is (Frequency of a.c. 
)
. The magnetic flux through the rod is 
and its cross-sectional area is 
. The magnetic permeability of the rod in 
is
long. If the length of the potentiometer wire is increased without changing the cell, the balancing length will (Driving source is not changed)
‘ at a height ‘h’ above the earth’s surface is 
then 
radius of earth)
‘ has maximum angular displacement ‘ 
‘. The maximum kinetic energy of the bob of mass ‘ 
. If length and breadth are reduced to 
rd of initial value and temperature is raised to 
then energy emitted per second becomes
‘ are separated by a distance ‘ 
. On this wave, how far away are the two points having phase difference of 
?
‘. Then the sag of bending of beam is ( 
has moment of inertia ‘I’ about an axis passing through its centre and perpendicular to its plane. Disc is melted and recast into a solid sphere. The moment of inertia of a sphere about its diameter is
than second overtone of open pipe. The fundamental frequency of open end pipe will be A) 
B) 
D) 
is inserted symmetrically and one end of the combination is dipped vertically in water such that the lower end of the combination is at same level. The rise of water in the capillary tube is 
surface tension of water, 
density of water, ![]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-478d84af1027ee3593251b323a3fb181_l3.png "Rendered by QuickLaTeX.com")
, in water. Relation between ‘ 
, density of water 
)
and 
of same material are stretched by same tension. The radius of the string A is double the radius of string B. Transverse wave travels on string A with speed ‘ 
‘ and on string 
with speed ‘ 
‘. The ratio 
is
‘ at the end of second revolution, after the revolution has started then the tangential acceleration is
‘ connected to a horizontal spring performs S.H.M. with amplitude ‘
‘ is placed on it so that both the masses move together with amplitude 
, The ratio of 
is 
![\left[\frac{m_{1}}{m_{1}+m_{2}}\right]^{\frac{1}{2}}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-2b29b57ed39eb1f6c58436a799bc7bae_l3.png "Rendered by QuickLaTeX.com")
![\left[\frac{\mathrm{m}_{1}+\mathrm{m}_{2}}{\mathrm{~m}_{1}}\right]^{\frac{1}{2}}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-f41789fa421a8e3dd967c1a79e94c1ec_l3.png "Rendered by QuickLaTeX.com")
![\left[\frac{m_{2}}{m_{1}+m_{2}}\right]^{\frac{1}{2}}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-e261477e0e770b6b424c21c834fa7358_l3.png "Rendered by QuickLaTeX.com")
![\left[\frac{\mathrm{m}_{1}+\mathrm{m}_{2}}{\mathrm{~m}_{2}}\right]^{\frac{1}{2}}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-17db4e934120c4864100c1c60fc53b04_l3.png "Rendered by QuickLaTeX.com")
![[\frac{1}{3}]^{rd}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-9f96177eb515481513c54e551e5e8124_l3.png "Rendered by QuickLaTeX.com")
kinetic energy per unit volume of a gas![[\frac{2}{3}]^{rd}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-496e049a5aa2709ddb63a237a5e8e0be_l3.png "Rendered by QuickLaTeX.com")
kinetic energy per unit volume of a gas![[\frac{3}{4}]^{th}](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-152c9f0a76e8d19379623b976244d69f_l3.png "Rendered by QuickLaTeX.com")
kinetic energy per unit volume of a gas
kinetic energy per unit volume of a gas
’, the apparent frequency of emitted note is ‘
’. When the observer moves away from the source with velocity ‘
’. If ‘
then 
where ‘R’ is the universal gas constant and ‘
’ is molar specific heat at constant volume. The gas is made up of molecules which are
through 
are in the ratio : 
is removed from the circuit, the phase difference between current and voltage is 
. If instead 
is removed from the circuit, the phase difference is again 
(2) 
(3) zero (4) 
. When tension in 
. If the frequency of 
, the original frequency of B will be : 
? (1) 
(2) 
(3) 
(4) 
of a substance is : 
J 
) (3) Hydrogen atom (4) Singly ionised helium atom ( 
length having 100 turns carries a current of 
. The magnetic field at the centre of the solenoid is: 
) 
speed of electromagnetic waves) 
) with temperature (T) For copper?
. The mass of the water in the capillary is 
. Another capillary tube of radius 
is immersed in water. The mass of water that will rise in this tube is : 
. The electric potential due to the dipole at a point at a distance of 
from the centre of the dipole, situated on a line making an angle of 
with the dipole axis is : 
from the top of a tower. It hits the ground after some time with a velocity of 
. The height of the tower is : 
(1) 
(2) 
(3) 
(4) 
(2) 
(3) 
(4) 
and temperature 
. Its density is : 
(2) 
(3) 
(4) 
![\left[ ML ^{0} T -2\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-02690e559c9f7e64a5e769eed00cfd2f_l3.png "Rendered by QuickLaTeX.com")
(2) ![\left[M L^{-1} T^{-2}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-1aa450011d60c40d511cca25fae244dc_l3.png "Rendered by QuickLaTeX.com")
(3) [ MLT-2] (4) ![\left[ ML ^{2 T -2}\right]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-41ff3b4626d6d04172ef3d45389c847a_l3.png "Rendered by QuickLaTeX.com")
is coming from a star. The limit of resolution of telescope whose objective has a diameter of 
is:
rad 
has a charge of 
distributed uniformly. what is the magnitude of electric field at a point 
from the centre of the sphere? ![\[\left(\frac{1}{4 \pi \varepsilon_{0}}=9 \times 10^{9} Nm ^{2} / C ^{2}\right)\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-ed955cd975489487a318f2e52b7fae86_l3.png "Rendered by QuickLaTeX.com")
is the magnification produced by the mirror] 
and 
and 
and 
and 
and 
and 
and b; 
and 
and 
and 
and 
and 
and 
. The road is banked at an angle 
is applied across an ideal capacitor C: 
, lags voltage 
by 
.