When a beam of white light is allowed to pass through convex lens parallel to principal axis, the different colours of light converge at different point on the principle axis after refraction. This is called :

A vessel of depth '$$d$$' is half filled with oil of refractive index $$n_1$$ and the other half is filled with water of refractive index $$n_2$$. The apparent depth of this vessel when viewed from above will be-

An ice cube has a bubble inside. When viewed from one side the apparent distance of the bubble is $$12\mathrm{cm}$$. When viewed from the opposite side, the apparent distance of the bubble is observed as $$4\mathrm{cm}$$. If the side of the ice cube is $$24\mathrm{cm}$$, the refractive index of the ice cube is

When one light ray is reflected from a plane mirror with $$30^{\circ }$$ angle of reflection, the angle of deviation of the ray after reflection is :

The critical angle for a denser-rarer interface is $$45^{\circ }$$. The speed of light in rarer medium is $$3\times 10^8\mathrm{m}/\mathrm{s}$$. The speed of light in the denser medium is:

An object is placed at a distance of 12 cm in front of a plane mirror. The virtual and erect image is formed by the mirror. Now the mirror is moved by 4 cm towards the stationary object. The distance by which the position of image would be shifted, will be

In a reflecting telescope, a secondary mirror is used to:

A monochromatic light wave with wavelength $${\lambda }_1$$ and frequency $$v_1$$ in air enters another medium. If the angle of incidence and angle of refraction at the interface are $$45^{\circ }$$ and $$30^{\circ }$$ respectively, then the wavelength $${\lambda }_2$$ and frequency $$v_2$$ of the refracted wave are:

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction. Reason R: The wavelengths of waves are different in different media. In the light of the above statements, choose the most appropriate answer from the options given below

A 2 meter long scale with least count of $$0.2\mathrm{cm}$$ is used to measure the locations of objects on an optical bench. While measuring the focal length of a convex lens, the object pin and the convex lens are placed at $$80\mathrm{cm}$$ mark and $$1\mathrm{m}$$ mark, respectively. The image of the object pin on the other side of lens coincides with image pin that is kept at $$180\mathrm{cm}$$ mark. The $$\%$$ error in the estimation of focal length is:

Given below are two statements : One is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason $$\mathbf{R}$$. Assertion A : For measuring the potential difference across a resistance of $$600\Omega$$, the voltmeter with resistance $$1000\Omega$$ will be preferred over voltmeter with resistance $$4000\Omega$$. Reason R : Voltmeter with higher resistance will draw smaller current than voltmeter with lower resistance. In the light of the above statements, choose the most appropriate answer from the options given below.

Equivalent resistance between the adjacent corners of a regular n-sided polygon of uniform wire of resistance R would be :

The number of turns of the coil of a moving coil galvanometer is increased in order to increase current sensitivity by $50 \%$. The percentage change in voltage sensitivity of the galvanometer will be :

The $\mathrm{H}$ amount of thermal energy is developed by a resistor in $10\mathrm{s}$ when a current of $4\mathrm{A}$ is passed through it. If the current is increased to $16\mathrm{A}$, the thermal energy developed by the resistor in $10\mathrm{s}$ will be :

The equivalent resistance between $$A$$ and $$B$$ of the network shown in figure;

The drift velocity of electrons for a conductor connected in an electrical circuit is $${\mathrm{V}}_{\mathrm{d}}$$. The conductor in now replaced by another conductor with same material and same length but double the area of cross section. The applied voltage remains same. The new drift velocity of electrons will be

The equivalent resistance between $A$ and $B$ is _________.

The charge flowing in a conductor changes with time as $$\mathrm{Q}(\mathrm{t})=\alpha \mathrm{t}-\beta {\mathrm{t}}^2+\gamma {\mathrm{t}}^3$$. Where $$\alpha ,\beta$$ and $$\gamma$$ are constants. Minimum value of current is :

With the help of potentiometer, we can determine the value of emf of a given cell. The sensitivity of the potentiometer is (A) directly proportional to the length of the potentiometer wire (B) directly proportional to the potential gradient of the wire (C) inversely proportional to the potential gradient of the wire (D) inversely proportional to the length of the potentiometer wire Choose the correct option for the above statements :

Ratio of thermal energy released in two resistors R and 3R connected in parallel in an electric circuit is :