Test: Physics - 3 - UPSC MCQ

In our houses, the frequency of alternating voltage supplied is 50 Hz, i.e. 50 times per second. In America, frequency of A.C. line is 60 Hz.

The intersected area of magenta and yellowcoloured circles will have red colour. The intersected area of cyan and magenta coloured circles will have blue colour. Magenta = Red + Blue Cyan = Blue + Green

Sound travels in rocks in the form of longitudinal elastic waves only.

Pressure and Coefficient of Elasticity have the same unit i.e. Nm-2 (Newton per metre square) Other important units: Rate of Flow: m3s-1 Acceleration: ms-2 Rydberg constant: 1/m Gas constant: J/K Impulse: Ns Moment of Force: Nm
 

Joule denoted by coulomb–volt. Watt denoted by amp²–ohm. Volt denoted by henery–amp/sec. Coulomb denoted by farad–volt.

Heat is a form of energy. Heat can be reflected by mirror. Heat can pass through a vacuum. Heat is transferred by thermal radiation. Heat cannot conduct through a vacuum because that requires molecules to move to carry the thermal energy.

Ultrasonic waves can produce perfectly homogeneous solution. It is used in homogenising milk cosmetics, etc.

According to the modern theory of nature of light, the light has both wave and particle nature.

The electrostatic force between two charges is inversely proportional to the square of the distance between the charges.

To produce light, a CFL uses mercury vapour and phosphorus while an LED lamp uses semiconductor material.

The function of the moderator is to slow down the neutrons.

The term Dolby B or Dolby C printed on tape recorders and other sound systems refers to noise reduction circuit.

A man inside an artificial satellite feels weightlesness because the force of attraction due to earth i.e. g (= acceleration due to gravity) is zero.

Due to the surface tension, a liquid drop tends to assume a spherical shape to minimise the surface area.

Because of the entire chamber of the refrigerator is cooled quickly due to convection.

The velocity of sound in air increases as the humidity increases.

Due to high penetrating power, the properties of interference, diffraction and polarization are not possible in X-ray.

Galvanometers are electrical devices used for the detection or measurement of the electric currents

When alpha, beta and gamma rays carry same momentum, then all have same wavelength as λ = h / P  where λ = wavelength, P = momentum and h = Plank’s constant (= 6.62 × 10^{– 34} Js).

The fraction of a ball floating inside the liquid depends only upon density of the liquid and the ball.