Physics Test - ...

A train moves towards a stationary observer with speed 34 m.s⁻¹. The train sounds a whistle and its frequency registered by the observer is f₁. If the train's speed is reduced to 17 m.s⁻¹, the frequency registered is f₂. If the speed of sound is 340 m.s⁻¹, then the ratio f1 / f2

There are four light weigh rod samples A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are note

(i) A is feebly repelled

(ii) B is feebly attracted

(iii) C is strongly attracted

(iv) D remains unaffected

Which one of the following is true?

A manometer connected to a close tap reads 3.5×10⁵ N.m⁻². When the valve is opened, the reading of manometer falls to 3.0×10⁵ N.m⁻², then velocity of flow of water is

Consider the spectral line resulting from the transition n = 2 → n = 1 in the atoms and ions given below. The shortest wavelength is produced by

A long solenoid with 10 turns/cm and a radius of 7 cm carries a current of 20 / π mA. A current ii exists in a straight conductor located along central axis of the solenoid. What is the net magnetic field at a point inside the solenoid where the net magnetic field makes an angle 45^o with axial direction ?

A disc is rotating with an angular velocity ω₀. A constant retarding torque is applied on it to stop the disc. The angular velocity becomes ω₀ /2 after n rotations. How many more rotations will it make before coming to rest ?

In the figure shown the current flowing through 2 R is

A unknown circuit element X is connected in series with a resistor R to an AC source. If V_AB=V_AC (rms value). than X is-

The equivalent capacitance of the combination of three capacitors, each of capacitance C shown in figure between points A and B is