Search, filter, and study UPSC Civil Services & IFoS Physics past year questions with rigorous derivations, formulas, and step-by-step solutions.
A body moving in an inverse square attractive field traverses on elliptical orbit with eccentricity e and period \gamma. Find the time taken by the body to traverse the half of the orbit that is nearer the centre of force. Explain briefly why a comet spends only 18\% of its time on the half of its orbit that is nearer the sun.
(i) The distance between the centres of the carbon and oxygen atoms in the carbon monoxide (CO) gas molecule is 1.130\times10^{-10}\ \mathrm{m}. Locate the centre of mass of the molecule relative to the carbon atom.
(ii) Find the centre of mass of a homogeneous semicircular plate of radius a.
Using Euler's equations for a force free motion of a rigid body, show that the Kinetic energy remains constant throughout the motion of the rigid body.
Four solid spheres A, B, C, and D each of mass m and radius a, are placed with their centres on the four corners of square of side b as shown in the figure below:
Calculate the moment of inertia of the system about one side of the square, Also, calculate the moment of inertia of the system about a diagonal of the square.
Design a transistor based Colpitt oscillator which can oscillate at 9\,\mathrm{MHz}. Explain how the oscillations are created and sustained.
Draw the device structure of a p-n junction solar cell and explain how light energy is converted into electrical energy. Draw and explain its I-V characteristics.
Differentiate between n-p-n and p-n-p transistors. Give their device structure and biasing circuits when used as an amplifier.
Describe an operational amplifier based integrator. Using operational amplifier integrators, design a circuit to solve the following differential equation: \frac{d^2v}{dt^2}+2\frac{dv}{dt}+3v=0
Show that any arbitrary rotation axis is not permitted in a crystal lattice.
Distinguish between a superconductor and perfect conductor. Explain what is a Cooper pair.
C$.
Find an expression for lattice specific heat of a solid, and its low and high temperature limits. What is Debye temperature?
Explain the term critical magnetic field in a superconductor. How does the critical magnetic field vary with temperature in Type-I and Type-II superconductors ? What is Meissner effect ?
Describe the motion of an electron in one dimensional periodic potential and show that it leads to formation of bands of allowed and forbidden states in the electron energy spectrum. How are the conductors, semiconductors and insulators discriminated on the basis of band structure?
With a suitable circuit diagram and theory explain the use of OP-Amps as
(i) Adder, and
(ii) Integrator.
What are called intrinsic and extrinsic semiconductors ?
Construct the following function with logic gates : Y = (A + B) (C + D + E) (F + G + H + I) (JKL)
Explain the operation of NOR gate with a logical diagram and truth table. Show how NOR gate can be used as Universal gate.
Describe the quark model. Obtain the quark composition of baryons and mesons.
Compute the density of a typical nucleus and find the resultant mass, if we could manufacture a nucleus with a radius of 1\text{ cm}.