List of top Physics Questions asked in Punjab PMET

An electron tube was sealed-off during manufacture at a pressure of $ 1.2\times 10^{-7}mm $ of mercury at $ 27^{\circ}C $ . Its volume is $ 100\,cm^{3} $ . The number of molecules that remain in the tube is

The given figure gives electric lines of force due to two charges $ q_{1}$ and $q_{2}$ . What are the signs of the two charges?

A block is resting on a piston which is moving vertically with SHM of period $1\, s$ . At what amplitude of motion will the block and piston separate?

Two simple harmonic motions are given by $ x=A\sin (\omega t+\delta ) $ and $ y=A\sin \left( \omega t+\delta +\frac{\pi }{2} \right) $ act on a particle simultaneously, then the motion of particle will be

Three point charges $ q,\,-2q $ and $ -2q $ are placed at the vertices of an equilateral triangle of side $ a $ . The work done by some external force to increase their separation to $ 2a $ will be

The shortest wavelength of the Brackett series of hydrogen like atom (atomic number $ =Z$) is the same as the shortest wavelength of the Balmer series of hydrogen atom. The value of $Z$ is

Two planets $ A $ and $ B $ have the same material density. If the radius of $ A $ is twice that of $ B $ , then the ratio of escape velocity $ \frac{v_{A}}{v_{B}}$ is

A radioactive element $ x $ converts into another stable element $ y $ . Half-life of $ x $ is $ 2h $ , initially only $ x $ is present. After time $ t $ , the ratio of atoms of $ x $ and $ y $ is found to be $ 1:4 $ , then $ c $ in hour is

Two sources are at a finite distance apart. They emit sound of wavelength $ \lambda $ . An observer situated between them on line joining the sources, approaches towards one source with speed $u$ , then the number of beats heard per second by observer will be

A man goes at the top of a smooth inclined plane. He releases a bag to fall freely and himself slides down on inclined plane to reach the bottom. If $u_{1}$ and $u_{2}$ are the velocities of the man and bag respectively, then

A closely wound flat circular coil of $25$ turns of wire has diaineter of $10\, cm$ which carries current of $4\, A$, the flux density at the centre of a coil will be

A car moves on a circular road. It describes equal angles about the centre in equal intervals of time. Which of the following statements about the velocity of the car is true?

In the figure, pendulum bob on left side is pulled aside to a height h from its initial position. After it is released it collides with the right pendulum bob at rest, which is of same mass. After the collision the two bobs stick together and raise to a height

A body is thrown vertically up with certain initial velocity. The potential and kinetic energies of the body are equal at a point P in its path. If the same body is thrown with double the velocity upwards, the ratio of potential and kinetic energies of the body when it crosses the same point, is

Three charges $ 1\mu C, $ $ 1\mu C $ and $ 2\mu C $ are kept at vertices of $A, B$ and $C$ of an equilateral triangle $ABC$ of $ 10\,cm $ side respectively. The resultant force on the charge at $C$ is

In Ramsden eyepiece, the two planoconvex lenses each of focal length $ f $ are separated by a distance $ 12\,cm $ . The equivalent focal length (in $ cm $ ) of the eyepiece is

A liquid drop of radius $ R $ breaks into $64$ tiny drops each of radius $ r $ . If the surface tension of the liquid is $ T $ , then the gain in energy is

A liquid does not wet the solid surface if the angle of contact is

A diverging meniscus lens of $ 1.5 $ refractive index has concave surfaces of radii $ 3 $ and $ 4\,cm. $ The position of the image, if an object is placed $ 12\,cm $ in front of the lens, is

A clock which keeps correct time at $20^{\circ} C$, is subjected to $40^{\circ} C .$ If coefficient of linear expansion of the pendulum is $12 \times 10^{-6} /{ }^{\circ} C$. How much will it gain or lose time ?

A stress of $3.18 \times 10^{8} Nm ^{-2}$ is applied to a steel rod of length $1\, m$ along its length. Its Young's modulus is $2 \times 10^{11} N-m^{-2}$. Then, the elongation produced in the rod (in $mm$ ) is

A sphere of mass $m$ moving with constant velocity $ u $ , collides with another stationary sphere of same mass. If $e$ is the coefficient of restitution, the ratio of the final velocities of the first and second spheres is

A body of mass $ 2\,kg $ is thrown up vertically with kinetic energy of $ 490\,J $ . If $ g=9.8\,m/s^{2} $ , the height at which the kinetic energy of the body becomes half of the original value, is

The apparent weight of a person inside a lift is $ w_{1}$ when lift moves up with a certain acceleration and is $ w_{2}$ when lift moves down with same acceleration. The weight of the person when lift moves up with constant speed is

Given two vectors $\vec{ A }=-\hat{ i }+2 \hat{ j }-3 \hat{ k }$ and $\vec{ B }=4 \hat{ i }-2 \hat{ j }+6 \hat{ k }$. The angle made by $(\vec{ A }+\vec{ B })$ with $x$-axis is