A star is receding away from earth with a velocity of . if the wavelength of its spectral line is , then doppler shift will be
A Doppler shift is a phenomenon of a change in frequency based on the observer’s point of view. The most... View Article
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If velocity (v), time (t) and mass (m) are taken as fundamental quantities, then dimensional formula for gravitational potential would be___
Dimensional analysis is the practice of checking relations between physical quantities by identifying the dimensions of the physical quantities. These... View Article
An electric current of 3 A passes through a wire of resistance 15 ω. How much heat will be developed in 1 minute?
Given An electric iron of resistance 15 Ω takes a current of 3 A Find out We have to calculate the... View Article
The radii of curvature of the surfaces of a double convex lens are 20 cm and 40 cm respectively, and its focal length is 20 cm. What is the refractive index of the material of the lens?
The refractive index is the measure of bending of a light ray when passing from one medium to another. It... View Article
A time varying power P=2t is applied on a particle of mass m. Find kinetic energy and velocity of particle as function of time
Power is a physical concept with several different meanings, depending on the context and the available information. We can define... View Article
Static electricity can be produced by______ (a) Only induction (b) Only friction (c)Only chemical reaction (d) Induction and friction
The correct answer is (d) Induction and friction Solution Static electricity refers to an imbalance between the electric charges in... View Article
A recurring deposit account of Rs 1,200 per month has a maturity value of Rs 12,440. If the rate of interest is 8% and the interest is calculated at the end of every month; find the time (in months) of this Recurring Deposit Account.
Given As per the given data P=Rs.1200 Nmberofmonths=n Intrest rate=8% MaturityAmount=Rs.12440 Find out We have to determine the time of this... View Article
We wish to obtain same sized image of an object, using a concave mirror of focal length 15 cm. where should be the object placed from the mirror?
The real and inverted image produced by a concave mirror becomes of equal size to the object when both object... View Article
A closed loop carrying current I lies in the x-z plane. The loop will experience a force if it is placed in a region occupied by a uniform magnetic field along: (a) x-axis (b) y-axis (c)z-axis (d) none of these
The correct answer is (d) none of these Solution A closed loop carrying current I lies in the x-z plane. From... View Article
The given figure gives a match stick pattern of triangles. Find the general rule that gives the number of matchsticks in terms of the number of triangles.
Solution From the figure we observe that in the given matchstick pattern, the number of matchsticks are 3, 5, 7... View Article
A cone, a hemisphere and a cylinder stand on equal bases of radius r and have equal heights h.Prove that their volumes are in the ratio 2:3:1
Given A cone, a hemisphere and a cylinder stand on equal bases of radius r and have equal heights h.... View Article
The difference between a two digit number and the number obtained by the interchanging the digits is 27. What is the difference between the two digits of the number?
Given The difference between a two digit number and the number obtained by the interchanging the digits is 27 Find... View Article
In how many ways can 5 boys and 5 girls sit in a circle so that no two boys sit together?
Permutation relates to the act of arranging all the members of a set into some sequence or order. The combination is... View Article
Find out the correct option from the following. (a) The magnification is positive for all virtual images and is negative for all real images. (b) The magnification of the concave lens and convex mirror is always positive whereas the magnification of the convex lens and concave mirror can be positive or negative depending on the position of the object before the lens. A. Only (a) is true. B. Only (b) is true. C. Both (a) and (b) are true. D. Both (a) and (b) are false.
Magnification is the increase in the image size produced by spherical mirrors with respect to the object size. It is... View Article
After spending 80% of his income and giving 10% of the reminder to a charity, a man has Rs.46260 left with him. Find his income.
After spending 80% of his income and giving 10% of the remainder to a charity, a man has Rs.46260 left... View Article
If a line makes angles 90°, 135°, 45° with the x, y and z-axes respectively, find its direction cosines.
Let the direction cosines of the line be l, m and n. Here let α = 90°, β = 135°... View Article
If (z3 – 3)2 16 = 0 then the value of |z| is
Modulus of the complex number is the distance of the point on the argand plane representing the complex number z... View Article
The sum of the digits of a 3 digit number is subtracted from the number. The resulting number is always_____
The sum of the digits of a 3 digit number is subtracted from the number. The resulting number is always Divisible... View Article
If three equal charges q are placed at the vertices of an equilateral triangle of side l, what is the net potential energy of the system?
The electric potential at a point in an electric field is defined as the amount of work done in moving... View Article
The internal bisector of an angle of a triangle divides the opposite side internally in the ratio of the corresponding sides containing the angle. Prove it.
GivenConsider a triangle ABCLet AD be the internal bisector of ∠BAC which meet BC at D To Prove BD/ DC... View Article
