Physics NCERT Exemplar Solutions Class 12th Chapter Nine

A point source of light S, placed at a distance 60cm infront of the centre of a plane mirror of width 50cm, hangs vertically on a wall. A man walks inform of the mirror along a line parallel to the mirror at a distance 1.2m from it (see in the figure). The distance between the extreme points where he can the image of the light source in the mirror is………….cm

A body is projected vertically upward from the surface of earth with a velocity equal to one third of escape velocity. The maximum height attained by the body will be:

Light travels in two media M₁ and M₂ with speeds 1.5 * 108 ms1 and 2.0 * 108 ms1 respectively. The critical angle between them is:

Given below are two statements : one is labeled as Assertion A and the other is labeled as Reason R.

Assertion A : For a simple microscope, the angular size of the object equals the angular size of the image.

Reason R : Magnification is achieved as the small object can be kept much closer to the eye that 25cm and hence it subtends a large angle.

In the light of the above statements, choose the most appropriate answer from the options given below:

Given below are two statements : one is labeled as Assertion A and the other is labeled as Reason R.

Assertion A : For a simple microscope, the angular size of the object equals the angular size of the image.

Reason R : Magnification is achieved as the small object can be kept much closer to the eye that 25cm and hence it subtends a large angle.

In the light of the above statements, choose the most appropriate answer from the options given below

The incident ray, reflected ray and the outward drawn normal are denoted by the unit vectors $\overrightarrow{a},\overrightarrow{b}and\overrightarrow{c}$ respectively. Then choose the correct relation for these vectors.

The length of metallic wire is ${\mathcal{l}}_1$ when tension in it is $T_1$ . It is ${\mathcal{l}}_2$ when the tension is T₂. The original length of the wire will be

In experiment of find acceleration due to gravity (g) using simple pendulum, time period of 0.5s is measured from time of 100 oscillation with a watch of 1 s resolution. If measured value of length is 10 cm known to 1 mm accuracy, The accuracy in the determination of g is found to be x%. The value of x is_______.

In an experiment with a convex lens, The plot of the image distance (v') against the object distance $\left(\mu \text{'}\right)$ measured from the focus gives a curve v $\text{'}\mu \text{'}$ = 225. If all the distances are measured in cm. The magnitude of the focal length of the lens is__________cm.

An object 'O' is placed at a distance of 100 cm in front of a concave mirror of radius of curvature 200 cm as shown in the figure. The object starts moving towards the mirror at a speed 2 cm/s. The position of the image from the mirror after 10 s will be at________cm.