Physics: 2017: CBSE: [All India]: Set – III

Angle of minimum deviation is directly proportional to the refractive index. Refractive index of red light is less than the refractive index of violet light in glass prism. Thus, angle of minimum deviation will decrease if the incident violet light is replaced by red light.

The phenomenon of Photoelectric effect shows the quantum nature of electromagnetic radiation.

The direction of induced currents in both the ring can be predictedusing Lenz’s lens.

As, induced current opposes the cause of increasing of magnetic flux. So, it will be clockwise in ring 1 and anticlockwise in ring 2.

The electric and magnetic field vectors will be in the Y-Z plane. They will be mutually perpendicular.

H = I²Rt,is known as Joule’s law of heating.

Where H is the amount of heat produced when a current I flows through a conductor of resistance R for a time t. In joule’s law of heating, H is directly proportional to resistance of the material. Hence, nichrome offers higher resistance than copper wire, so, it will heat-up faster.

(a) Permanent magnets are made up of the materials which have high retentivity and high coercivity.

(b)Electromagnets are made up of the materials which have high permeability and low retentivity.

The intensity pattern for a single slit diffraction is as shown below:

The intensity pattern for a double slit interference is as shown below:

Double Slit interference

Differences in the intensity patterns:

1. In interference, the region of minimum intensity is perfectly dark whereas in diffraction, it is not perfectly dark.

2. The width of fringes in interference is always equal. On the other hand, in diffraction, the width of fringes is never equal.

When an unpolarised light passes through polariser P₁ , its intensity becomes I₀/2 and light becomes polarised.

When this polarised light passes through P₂ , then the intensity is given by “The Law Of Malus”

Now the intensity pattern is :

Initially,the capacitor is uncharged. When it is connected across a battery,(top plate of the capacitor is connected to the positive terminal of the battery and the bottom plate is connected to the negative terminal) positive charge starts to accumulate on the top plate of the capacitor and negative charge begins to accumulate on the bottom plate. At steady state capacitor becomes fully charged with voltage equal to the supply voltage,hence from now it behaves like open circuit as net voltage in circuit is zero so current is also equal to zero.

So, when an uncharged capacitor is connected to a battery, current flows for a very short duration, until the capacitor is fully charged, and then flow of current stops.

As transition takes place from n=3 to n=2, so, it is Balmer series of hydrogen spectrum.

The wavelength is given by