Question Discussion & Solution

The correct answer is option 3 i.e Backup.

Key Points

• Protecting data by copying it from the original source to a different destination is called Backup.
  • Backups can be used to recover data after its loss from data deletion or corruption.

Additional Information​ 

• The activity of creating sectors and tracks on a hard disk is called Formatting.
• The process of unauthorised access to information system is called Hacking.
  • One who does hacking is called Hacker.
  • Hackers are mainly classified as White Hat Hackers, Black Hat Hackers, Gray Hat Hackers.
• Data diddling is the unauthorised changing of data before or during their input to a computer system.

Four members: A, B, C, D

Using the symbols in the table given below, we can draw the following family tree:

1) B is the husband of A

2) C is the sister of B

3) D is the brother of A

Hence, C is D’s brother-in-law's sister.

Given: MADRAS is coded as NBESBT.

Logic: Adding 1 to the positional values of the letter, as shown below:

Similarly,

Hence, CPNCBZ is the correct answer.

Given that-

We add upper two number then divide by 2 and then square of that number we get lower number.

(6 + 4) ÷ 2 = 5² = 25

(3 + 1) ÷ 2 = 2² = 4 

Similarly,

(5 + 3) ÷ 2 = 4² = 16

Alternate Method 

Figure 1: 6 × 4 + 1 = 25 

Figure 2:  3 × 1 + 1 = 4

similarly, 

Figure 3:  5 × 3 + 1 = 16

Hence, "16" is the correct answer.

The correct answer is Curvature of the lens.

Important Points

• Focal length of a lens depends on its curvature and the medium outside the lens.

Additional Information

• The ability of a lens to converge or diverge light rays depends on its focal length.
  • For example, a convex lens of short focal length bends the light rays through large angles, by focussing them closer to the optical centre.
  • Similarly, the concave lens of a very short focal length causes a higher divergence than the one with a longer focal length.
• The degree of convergence or divergence of light rays achieved by a lens is expressed in terms of its power.
  • The power of a lens is defined as the reciprocal of its focal length.