DC Circuit | Old is Gold XII | 

Short Questions 1.      An ammeter is always connected in series. Why? 2.      Why do we use connecting wires made of copper? 3.      What are the factors on which the resistance of a conductor depends? 4.      Can the potential difference across a battery be greater than its emf? 5.      Two bulbs of 60 W and 100 […]

Mechanical Waves | Important Questions | 

1)      What do you mean by water waves? 2)      Why sound produced at a distance can be heard distinctly at night than in day time? 3)      Is velocity of sound more in damp air or in dry air? Explain. 4)     A boat at anchor is rocked by waves whose crest is 100 feet apart and whose […]

Variation of ‘g’ due to rotation or latitude 

Let us consider the earth to be a spherical ball of mass ‘M’ and radius ‘R’. An object of mass ‘m’ is at point P at latitude φ, when the earth is not rotating the weight of the object is mg. But earth is rotating with angular velocity ω. So, the object is moving in a circular […]

Variation of ‘g’ due to depth 

Let us consider the earth to be spherical mass of ‘M’ and radius ‘R’. A body of mass ‘m’ is placed initially on the surface and finally taken x distance deep into the earth. We know acceleration due to gravity on the surface of earth is This expression shows that acceleration due to gravity decreases […]

Variation of ‘g’ due to Height (Altitude) 

Let us consider the earth to be perfectly spherical of mass ‘M’ and radius ‘R’. A body of mass ‘m’ is initially placed on the surface of the earth. We know, Acceleration due to gravity is given by This expression shows that acceleration due to gravity decreases as we go higher from the surface of […]

Relation between ‘g’ & ‘G’ 

Let us consider a body of mass ‘m’ is placed on the surface of the earth of mass ‘M’ & radius ‘R’. Then from Newton’s Law of Gravitation, So, from above expression we infer that acceleration due to gravity is dependent only on mass and radius of earth. The ‘g’ doesn’t depend on the mass […]


Newton’s law of Gravitation It states that everybody in this universe attracts other body with a force which is proportional to the product of the masse of two bodies and inversely proportional to the square of the distance between their centers. From Newton’s law of Gravitation, If two masses of unit mass are placed at […]

Variation of g due to shape of the earth 

The shape of the earth is bulged at the equator and flat at the poles. This means earth has large radius at the equator than at poles. We know that, So, acceleration due to gravity is more at the pole than at the equator.


INCLINED PLANE Any plane surface which makes an angle q with the horizontal surface is called inclined plane such that0

Gallilean’s Telescope 

GALILEAN’S TELESCOPE Galilieo in 1906 constructed a telescope which provides an erect image of an object only with the help of two lenses .Galilean’s telescope is used to see the object on earth . Construction of telescope The Galilean’s telescope consists of two lenses.Objective Eye piece Objective Objective is a convex lens of large focal […]