How does a moving coil galvanometer operate?
The gravitational potential energy of two masses at a distance 2.0 m apart is - 8.0 J. What external work must be done on this system to separate the masses to a distance of 4.0 m?
A straight current-carrying conductor is placed within an external magnetic field as shown below.
A simple DC motor has n turns of wire in the armature and has an area of A m2. A current of I amperes passes through the armature. The plane of the armature is at 0 o to the direction of the magnetic field of strength B Teslas. What is the torque on the armature if the area and the current are doubled and the armature is at an angle of 60 o to the magnetic field direction?
Which of the following correctly describes a photon?
Inside a discharge tube producing cathode rays, a freely rotatable wheel is mounted. When cathode rays fall on it the wheel starts rotating. What does this experiment indicate about cathode rays?
A person stands on a scale in an elevator. He notices that the scale reading is lower than his normal ‘weight’. Which of the following could possibly describe the motion of the elevator?
A moon of a planet Rusean has an orbital period of 5 days and is at a distance of 5 units from the centre of the planet. Another moon is discovered at a distance of 20 units from the centre of Rusean. Which of the following will be closest to the orbital period of the newly discovered moon?
AC induction motors are commonly used in small power tools around the home. Which of the following statements correctly describes the working of an AC induction motor?
A copper ring hangs vertically from a thread with its axis along the axis of a coil as shown in the diagram.
The following is a list of some possible properties of high temperature superconductors. Some may be incorrect.
A ball is projected horizontally with a speed of 40 ms-1 from the top of a cliff on the surface of the Earth. What will be its approximate speed 3.0 s later if there were no air resistance?
Which statement, according to the BCS theory of superconductivity, is correct?
The minimum initial velocity required by a space probe to just escape the gravitational pull of a planet is called escape velocity. Which of the following quantities does NOT affect the magnitude of the escape velocity?
The figure below shows a straight wire carrying a steady current from X to Y. The wire is suspended between the poles of two similar permanent magnets, each of which produces a uniform magnetic field between the N and S poles.