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The momentum of a photon of an electromagnetic radiation is $3.3\times {10}^{-29}kgm{s}^{-1}$. What is the frequency of the associated wave?

Mass is distributed uniformly over a thin triangular plate and positions of two vertical are given by $(1,3)$ and $(2,-4)$. What is the position of third vertex, if centre of mass of the plate lies at the origin?

Which of the following acceleration (a)-mass (m) graph is correct when force is constant?



जब बल नियत है, तब निम्नलिखित में से कौनसा त्वरण (a)-द्रव्यमान (m) आरेख सही है?

A proton and an $\alpha$-particle enter a uniform magnetic field at right angles to the field with the same speed. The ratio of the periods of $\alpha$-particle and proton is-

If two similar springs, each of spring constant $K_1$ are joined in series, the new spring constant and the time period would be changed by a factor of:

Find a
vector of magnitude 5 units, and parallel to the resultant of the
vectors

.

A boat crosses a river from port A to port B, which are just on the opposite side. The speed of the water is $V_W$ and that of boat is $V_B$ relative to water. Assume $V_B=2V_W.$ What is the time taken by the boat, if boat has to cross the river directly on the AB line? ($D=$ width of river)

In the given figure find

(i) position of $A$ with respect to $B$

(ii) position of $O$ with respect to $B$

The radius of gyration of rod of length ${}^{\prime }{L}^{\prime }$ and mass ${}^{\prime }{M}^{\prime }$ about an axis perpendicular to its length and passing through a point at a distance $L/3$ from one of its ends is

Explain Archimedes principle?

A mixture of $4\text{g}$ of hydrogen and $8\text{g}$ of helium at pressure $P=1.01\times {10}^5\text{Pa}$ and temperature $T=273\text{K}$ has a density of about

Two masses $A$ and $B$, each of mass $M$ are fixed together by a massless spring. A force acts on the mass $B$ as shown in the figure. If the mass $A$ starts moving away from mass $B$ with acceleration $‘a^{\prime }$, then the acceleration of mass $B$ will be :

A spherical ball $A$ of surface area $10{\text{cm}}^2$ is kept at the centre of a hollow spherical shell of area $20{\text{cm}}^2$. Surface of $A$ and inner surface of $B$ behave as black bodies. Both $A$ and $B$ are at $300\text{K}$. Find the radiation energy emitted per second by the inner surface of $B$.

A concave mirror is placed at the bottom of an empty tank with face upwards

and axis vertical. When sunlight falls normally on the mirror, it is

focussed at distance of 32 cm from the mirror. If the tank filled with water

upto a height of 20 cm, then the sunlight will now get focussed at

[UPSEAT 2002]

A liquid of density $\rho$ and surface tension $\sigma$ rises to a height $h$ in a capillary tube of diameter $d$. The potential energy of the liquid in the capillary tube is:
[Assume liquid to be perfectly wetting in nature]

A parallel beam of monochromatic light of wavelength $\lambda$ falls normally on a narrow slit of width $a$. The diffraction pattern is observed on a screen placed perpendicular to the direction of the incident beam. The phase difference between the waves coming from the edges of the slit at the position of the first maximum of the diffraction pattern is

A pulley mass arrangement is shown is the figure. A force of $50\text{N}$ is applied on the $2\text{kg}$ block. Find the acceleration of COM of the system.

Suppose an attractive nuclear forc eacts between two protons which may be written as $F=C\frac{e^{-kr}}{r^2}$ (a) Write down th edimensional formulae and appropriate SI unit of c and k. (b) supose that k = $1ferm{i}^{-1}$ and that the repulsive electric force between the protons is just balanced by the attractive nuclear force when the separation is 5 fermi. Find the value of C.

Two cars A and B are moving in same direction with a speed of 30km per hr. They are separated from each other by 5 km. Third car moving in the opposite direction meets the two cars after an interval of 4 mins. The speed of third car is ? ( use relative velocity to solve the problem)

1. 30km per hr

2. 25km per hr

3. 40km per hr

4. 45km per hr

The velocity at the maximum height of a projectile is $\sqrt{3}/2$ times of its initial velocity of projection which is $u=20{\text{ms}}^{-1}$. Find the range of projectile on the horizontal plane.

(Take $g=10{\text{m/s}}^2$)

In the circuit shown in the figure, time constant and steady state current will be

A body dropped from the top of a tower falls through $40m$ during the last two seconds of its fall. The height of tower is $(g=10m/s^2)$

A
hydrogen atom initially in the ground level absorbs a photon, which
excites it to the n
= 4 level. Determine the
wavelength and frequency of the photon.

A block of mass $0.1\text{kg}$ is held at rest against a wall applying a horizontal force of $5\text{N}$ on the block. If the coefficient of friction between the block and the wall is $0.5$, the magnitude of the frictional force acting on the block is

A steel frame (K = 45 $W{m}^{-1\circ }{C}^{-1})$ of total length 60 cm and cross sectional area 0.20 $c{m}^2$, forms three sides of a square. The free ends are maintained at ${20}^{\circ }C$ and ${40}^{\circ }$ C.Find the rate of heat flow through a cross section of the frame.

A regular polygon of $4$ sides is formed by bending wires of total length $1\text{m}$ which carries a current of $10\text{A}$. If the same polygon is reshaped into a circle with the same center then find the change in magnetic field at the center of the polygon ${}^{\prime }{O}^{\prime }$.

In an electromagnetic wave, the electric and magnetising fields are 100V $m^{-1}$ and 0.265 $A{m}^{-1}$. The maximum energy flow is

If the length of a simple pendulum at a given place is increased by 6 times, the ratio of the final to the initial time periods of the pendulum is .

A particle starts its motion from rest under the action of a constant force.if the distance covered in first 10 sec is S1 and that covered in the first 20 sec is S2 ,then

a. S2=2S1

b. S2=3S1

c. S2=4S1

d. S2=S1