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Newton's universal law of gravitation applies to ______.
Concept: undefined >> undefined
If three equal masses m are placed at the three vertices of an equilateral triangle of side 1/m then what force acts on a particle of mass 2m placed at the centroid?
Concept: undefined >> undefined
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A glass flask is filled up to a mark with 50 cc of mercury at 18°C. If the flask and contents are heated to 38°C, how much mercury will be above the mark? (α for glass is 9 × 10-6/°C and coefficient of real expansion of mercury is 180 × 10-6/°C)
Concept: undefined >> undefined
An electron of mass m and charge e initially at rest gets accelerated by a constant electric field E. The rate of change of de-Broglie wavelength of this electron at time t ignoring relativistic effects is ______.
Concept: undefined >> undefined
For a particle moving in vertical circle, the total energy at different positions along the path ______.
Concept: undefined >> undefined
From Brewster's law, except for polished metallic surfaces, the polarising angle ______.
Concept: undefined >> undefined
When an electron in hydrogen atom revolves in stationary orbit, it ______.
Concept: undefined >> undefined
A clock with an iron pendulum keeps the correct time at 15°C. If the room temperature is 20°C, the error in seconds per day will be near ______.
(coefficient of linear expansion of iron is 1.2 × 10-5/°C)
Concept: undefined >> undefined
Two gases A and B are at absolute temperatures of 360 K and 420 K, respectively. The ratio of the average kinetic energy of the molecules of gas B to that of gas A is ______.
Concept: undefined >> undefined
The Young's modulus of brass and steel are respectively 1.0 × 1011 Nm-2 and 2.0 × 1011 Nm-2. A brass wire and a steel wire of the same length are extended by 1 mm each under the same force. If the radii of brass and steel wire are RB and RS respectively, then ______.
Concept: undefined >> undefined
The triply ionised beryllium (Be+++) has the same electron orbital radius as that of the ground state of the hydrogen atom. The energy state (n) of triply ionised beryllium is ______.
(Z for beryllium = 4)
Concept: undefined >> undefined
The orbital frequency of an electron in the hydrogen atom ______.
Concept: undefined >> undefined
The speed of an electron in ground state energy level is 2.6 × 106 ms-1, then its speed in third excited state will be ______.
Concept: undefined >> undefined
When the temperature of an ideal gas is increased from 27°C to 227°C, its speed is changed from 400 ms-1 to vs, and Then vs is ______.
Concept: undefined >> undefined
When a particle oscillates simple harmonically, its kinetic energy varies periodically. If frequency of the particle is n, then the frequency of the kinetic energy is ______.
Concept: undefined >> undefined
A metal rod Y = 2 × 1012 dyne cm-2 of coefficient of linear expansion 1.6 × 10-5 per °C has its temperature raised by 20°C. The linear compressive stress to prevent the expansion of the rod is ______.
Concept: undefined >> undefined
Let Ee and Ep represent the kinetic energy of electron and photon, respectively. If the de-Broglie wavelength λp of a photon is twice the de-Broglie wavelength λe of an electron, then `E_p/E_e` is ______.
(speed of electron = `c/100`, c = velocity of light)
Concept: undefined >> undefined
Ultraviolet light of wavelength 300 nm and intensity 1.0 Wm−2 falls on the surface of a photosensitive material. If one percent of the incident photons produce photoelectrons, then the number of photoelectrons emitted from an area of 1.0 cm2 of the surface is nearly ______.
Concept: undefined >> undefined
In Bohr’s atomic model, speed and time period of revolution of an electron in n = 3 level are respectively.
Concept: undefined >> undefined
The extension in a wire obeying Hooke's law is x. The speed of sound in the stretched wire is v. If the extension in the wire is increased to 4x, then the speed of sound in a wire is
Concept: undefined >> undefined
