A boy stands straight in front of a mirror at a distance of 30 cm away from it. He sees his erect image whose height is  \(\cfrac { 1 }{ 5 } \) of his real height. The mirror he is using is _____________.

A man of length h requires a mirror of length at least equal to, to see his own complete image is _______________.

______ lenses are used in electron microscope.

____________ electrons occupy the conduction band.

______ theory explains photo electric effect.

Arrange the spectral lines H_α, H_β, H_γ, H_δ in the increasing order of their wavelength.

The particle size of ZnO material is 30 nm. Based on the dimension it is classified as _____.

The barrier potential of a silicon diode is approximately, ______.

In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to _____.

When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is \(\frac{V}{4}\). The threshold wavelength for the metallic surface is _____.

One of the of Young’s double slits is covered with a glass plate as shown in figure. The position of central maximum will,_____.

The phase difference between electric and magnetic field vectors in the electromagnetic waves?

A current of 2A flows through a circular coil of area 4π x 10^-2 m². The magnetic field at the centre of the coil is ________________.

For a given thermocouple for a given cold junction temperature, the inversion is 220°C. When the cold junction temperature is increased by 20°C, then the inversion temperature is __________________.

The unit of temperature coefficient of resistance is_______.

AC generator works on the principle of _____________.

In Fleming's right hand rule, the forefinger represents the direction of ____________.

A bird sitting on an insulated wire carrying a current feels quite safe because ____________.

The direction of electric field at a point the equatorial line due to an electric dipole is

In an electrical circuit, R, L, C, and AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and current in the circuit is \(\frac{\pi}{3}\). Instead, if C is removed from the circuit, the phase difference is again \(\frac{\pi}{3}\). The power factor of the circuit is

Which of the following is NOT true for electromagnetic waves?

An electric field \(\vec { E } =10x\hat { i } \) exists in a certain region of space. Then the potential difference V = V_o – V_A, where V_o is the potential at the origin and V_A is the potential at x = 2 m is _____.

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of ______.

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of different colours for its identification. The colour code sequence will be ______.