Consider the following statements about the 'Periscope': 1. It is primarily used in aircraft for navigation. 2. It allows soldiers in bunkers to see things outside. 3. It uses plane mirrors to reflect light. Which of the statements given above is/are correct?

The correct option is (c). Explanation A periscope is an optical instrument that allows an observer to view objects that are not in the direct line of sight. It is typically used to look over, around, or through obstacles, utilizing the laws of reflection. Statement-wise Analysis - Statement 1 is Incorrect. Periscopes are primarily used in submarines to view the surface while submerged, and in land warfare (tanks and bunkers) to observe surroundings without exposure. They are not primarily used in aircraft for navigation; aircraft rely on avionics, radar, and direct visual contact. - Statement 2 is Correct. In military applications, specifically in trench warfare or bunkers, periscopes allow soldiers to observe the battlefield and enemy movements while remaining safely concealed behind armor or earthworks. - Statement 3 is Correct. A simple periscope consists of a tube with two plane mirrors (or right-angled prisms) located at each end. These mirrors are inclined at an angle of 45° to the axis of the tube and are parallel to each other. This arrangement reflects light from the object down the tube and then to the observer's eye. Key Takeaway: A periscope functions based on the principle of multiple reflections of light. In its simplest form, it employs two plane mirrors placed parallel to each other at a 45° angle to change the path of light rays.

Consider the following statements about the 'Periscope': 1.… - NCERT Class 8 Science MCQ

NCERT Class 8 Science — Chapter 4: Light

mcqmedium

Consider the following statements about the 'Periscope':

It is primarily used in aircraft for navigation.
It allows soldiers in bunkers to see things outside.
It uses plane mirrors to reflect light.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 8 · Page 169

Options

A1 and 2 only
B2 only
C2 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (c).

Explanation

A periscope is an optical instrument that allows an observer to view objects that are not in the direct line of sight. It is typically used to look over, around, or through obstacles, utilizing the laws of reflection.

Statement-wise Analysis

Statement 1 is Incorrect. Periscopes are primarily used in submarines to view the surface while submerged, and in land warfare (tanks and bunkers) to observe surroundings without exposure. They are not primarily used in aircraft for navigation; aircraft rely on avionics, radar, and direct visual contact.
Statement 2 is Correct. In military applications, specifically in trench warfare or bunkers, periscopes allow soldiers to observe the battlefield and enemy movements while remaining safely concealed behind armor or earthworks.
Statement 3 is Correct. A simple periscope consists of a tube with two plane mirrors (or right-angled prisms) located at each end. These mirrors are inclined at an angle of 45° to the axis of the tube and are parallel to each other. This arrangement reflects light from the object down the tube and then to the observer's eye.

Key Takeaway: A periscope functions based on the principle of multiple reflections of light. In its simplest form, it employs two plane mirrors placed parallel to each other at a 45° angle to change the path of light rays.

Your note

More from Chapter 4: Light

With reference to the Periscope, consider the following statements: 1. It works on the principle of multiple reflections. 2. It uses two plane mirrors arranged at right angles to each other. 3. It allows viewing of objects that are not directly in the line of sight. Which of the statements given above are correct?

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With reference to image formation by a plane mirror, consider the following statements: 1. The image formed cannot be obtained on a screen. 2. The image appears at a greater distance behind the mirror than the object is in front. 3. The image undergoes lateral inversion. Which of the statements given above are correct?

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Consider the following statements about the image formed by a plane mirror: 1. It is inverted vertically. 2. It is of the same size as the object. 3. It appears to be at the same distance behind the mirror as the object is in front. Which of the statements given above is/are correct?

easy

In the context of the reflection of light, what does the term 'angle of incidence' refer to?

easy

With reference to the eye's ability to see, consider the following statements: 1. A normal eye can clearly see distant objects as well as objects nearby. 2. The minimum distance for distinct vision is constant at 50 cm for all ages. 3. In old age, eyesight may become foggy due to the eye lens becoming cloudy. Which of the statements given above is/are correct?

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