How will the image formed by a convex lens be affected if the central portion of lens is wrapped in black paper ?
answer: The full image will be formed, but it is less bright Explanation As a result of a huge number of... View Article
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How many Faradays of electricity are required to deposit 10 g of calcium from molten calcium chloride using inert electrodes? (molar mass of calcium = 40 g mol −1)
The equation is written as Ca2+ +2e− → Ca Number of moles of Ca= 10g /40g/mol =0.25mol 1 mole Ca... View Article
The work function of a surface of a photosensitive material is 6.2 eV. The wavelength of the incident radiation for which the stopping potential is 5V lies in the : A. infrared region B. X-ray region C. Ultraviolet region D. Visible region
We are given the value W=6.2eV for the work function of a photosensitive material’s surface. V=5V is the stopping potential... View Article
A proton, deutron and an α-particle enter a magnetic field perpendicular to field with same velocity. What is the ratio of the radii of circular paths?
Each of the three particles has a charge. The proton has a positive charge of +e, the deuteron has a... View Article
The northern plains are formed by a) force of convection b) interplay of himalayan rivers c) glacier erosion
Answer: (a) By the interplay of three river systems Indus, Ganga, and the Brahmaputra Explanation The Northern Plain was formed by... View Article
The periodic time of a body executing SHM is 4s. After how much interval from time t=0, its displacement will be half of its amplitude?
What is Simple Harmonic Motion? Simple Harmonic Motion or SHM is defined as a motion in which the restoring force... View Article
To obtain displacement current of 0.2 a between the plates of a capacitor of capacity 0.5 μf, what should be the rate of change of potential difference between the plates?
A capacitor is a two-terminal electrical device that possesses the ability to store energy in the form of an electric... View Article
What is the rest mass energy of electron?
The energy described by the Einstein equation is rest mass energy. The letter ‘e’ stands for electron charge. The letter... View Article
The oscillating magnetic field in a plane electromagnetic wave is given by: By=(8×10−6)sin[2×1011t+300πx]T (i) Calculate the wavelength of the electromagnetic wave. (ii) Write down the expression for the oscillating electric field.
What are Electromagnetic Waves? Electromagnetic waves are also known as EM waves. Electromagnetic radiations are composed of electromagnetic waves that... View Article
In the circuit shown below, the key K is closed at t=0. The current through the battery is
The inductor serves as an open switch at t = 0 since there is no current flowing through it. This... View Article
The mass of a lift is 500 kg. What will be the tension in its cable ifit moves down with an acceleration
Tension is a continual force that works on the connecting medium, such as a rope or cable. This is mostly... View Article
The maximum number of possible interference maxima for slit-separation equal to four times the wavelength in Young’s double-slit experiment is:
Answer: 9 Explanation Young’s double-slit experiment employs two coherent light sources separated by a small distance. These two light sources... View Article
The moment of inertia of a uniform circular disc of radius R and mass M about an axis passing from the edge of the disc and normal to the disc is
What is Moment of Inertia? Moment of inertia is defined as the quantity expressed by the body resisting angular acceleration... View Article
For a angular projection given to a projectile, find : (i) Maximum height, (ii) Time of flight, (iii) Horizontal range.
What is Projectile? A projectile is any object thrown into space upon which the only acting force is gravity. The... View Article
If the magnitude of two vectors are 4 and 6 and the magnitude of their scalar product is 12√2 , then what is the angle between these vectors?
A vector is a two-dimensional entity with both magnitude and direction. A vector can be visualised geometrically as a directed... View Article
A potential difference V is applied across a conductor of length ‘l’. How is the drift velocity affected when V is doubled and l is halved?
The formula for drift velocity is given by, |vd|=eτ/m x E But we know that E=V/l where V is the... View Article
Assertion: In javelin throw, the athlete throws the projectile at an angle more than 45∘. Reason: The maximum range does not depend upon angle of projection. (A) Both assertion and reason are the correct answer, reason is the correct explanation for assertion. (B) Both assertion and reason are correct. The answer reason is the incorrect explanation for the assertion. (C) Assertion is correct and reason is incorrect. (D) Both assertion and reason are incorrect.
A javelin’s route is identical to that of a projectile motion. So the formula of range in projectile motion is... View Article
A current carrying power line carries current from west to east .The direction of magnetic field 1m above is:
Answer: North to south Explanation The direction of the magnetic field surrounding a straight current carrying wire is determined by... View Article
Two identical glass (μg =3/2) equiconvex lenses of focal length f are kept in contact. The space between the two lenses is filled with water (μw =4/3). The focal length of the combination is
Water in between the lens can be considered to be a concave lens of refractive index of water as shown... View Article
An AC current is given by I = I0 + I1 sinωt then the rms value will be.
Alternating current is the current whose magnitude varies with time and reverse it direction periodically, i.e. after half-time period. The... View Article
