Dr. Sunil Kushwaha Solutions for Chapter: Light - Reflection and Refraction, Exercise 5: MCQs based on Practical Skill

Four students $A\mathit{,}\mathit{ }B\mathit{,}\mathit{ }C\mathit{ }$and $D$ carried out measurements of focal length of a concave mirror as shown in the four diagrams.

the best result will be obtained by students:-

Mohan, Sohan and Rahul separately measured the focal length of the same convex lens using the same distant tree as object. All of them measured the distance between the lens and the inverted image of the tree on the screen. Mohan obtained a sharp image on the screen and labelled the measured distance as ${\mathrm{f}}_1$

Sohan obtained a slightly smaller and somewhat blurred image on the screen. He labelled the measured distance as ${\mathrm{f}}_2$

Rahul obtained a slightly magnified and blurred image on the screen. He labelled the measured distance as ${\mathrm{f}}_3$.

The three measured values of focal length are likely to be related as—

To determine the focal length of a convex lens by obtaining a sharp image of a distant object, the following steps were suggested which are not in proper sequence —

$\left(\mathrm{I}\right)$ Hold the lens between the object and the screen.

$\left(\mathrm{II}\right)$ Adjust the position of the lens to form a sharp image.

$\left(\mathrm{III}\right)$ Select a suitable distant object.

$\left(\mathrm{IV}\right)$ Measure the distance between the lens and the screen.

The correct sequence of steps to determine the focal length of the lens is 

Mohan obtained a sharp inverted image of a distant tree on the screen placed behind the lens. He then moved the screen and tried to look through the lens in the direction of the object. He would see___

By using a convex lens, a student obtained a sharp image of his class-room window grill on a screen. In which direction should he move the lens to focus a distant tree instead of the grill?

A student focussed the image of a distant object using a device X on a white screen X as shown in the figure. If the distance of the screen from the device is $30 \mathrm{cm}$, select the correct statement about the device X.

A student obtained a sharp image of a burning candle, placed at the farther end of a laboratory table, on a screen using a concave mirror. For getting better value of focal length of the mirror, the subject teacher suggested him for focussing a well illuminated distant object. What should the student do?

Out of the five incident rays shown in the figure, the three rays that are obeying the laws of refraction and may be used for locating the position of image formed by a convex lens is _____.