Question Discussion & Solution

CONCEPT:

Force:

• The interaction which after applying on a body changes or try to changes the state of rest or state of motion is called force.
• It is denoted by F. The SI unit of force is Newton (N).

Force (F) = Mass (m) × acceleration (a)

• If more than one force is acting on a body, then the effect on the body is due to the net force.
• A stationary object on which no force is acting remains stationary.
• An object in motion continues to move with the same speed and direction when no force is acting on the object. This is Newton’s first law of motion. 

​CALCULATION:

Given:

Force = 20 N

Acceleration (a) = 2 m/s2

⇒ Force (F) = m a 

⇒ m = F/a = 20/2 = 10 kg.

So, option 4^th is correct.

Given series: 2, 5, 10, 17, 26, 37, 50, 65, 82, _________

The logic is:

2 + 3 = 5

5 + 5 = 10

10 + 7 = 17

17 + 9 = 26

26 + 11 = 37

37 + 13 = 50

50 + 15 = 65

65 + 17 = 82

82 + 19 = 101

After completing the figure draw bellow

Hence, option 3 is the correct answer.

The correct answer is Electric Heater.

Key Points

• Electric Heater is a device that can convert Electric energy into heat energy.
• In an electron tube, an electric heating element shaped in the form of a wire or ribbon is used to supply heat to a cathode; the element provides heat when a current is passed through it.
• Electric heaters also are used for domestic central heating and for materials processing in the industry for example heat pumps; electric furnace.

Additional Information

• Energy is the ability to do work.
• The  Law of conservation of energy:
  • Energy can neither be created nor be destroyed, only Energy can be converted from one form to another.
• These are some parts of the energy that convert one form to another:
  • Heat
  • Light
  • Motion
  • Electrical
  • Chemical
  • Gravitational

Important Points

The Logic here is as follows:

(1^st Number × 2^nd number) × 4 = 3^rd Number

In (6, 8, 192)

(1^st Number × 2^nd number) × 4

= (6 × 8) × 4

= 48 × 4

= 192 = 3^rd Number

Now check the all options,

Option (1) (12, 13, 263)

(1^st Number × 2^nd number) × 4

= (12 × 13) × 4

= 156 × 4

= 624 ≠ 3^rd Number

Option (2) (8, 11, 180)

(1^st Number × 2^nd number) × 4

= (8 × 11) × 4

= 88 × 4

= 352 ≠ 3^rd Number

Option (3) (11, 9, 396)

(1^st Number × 2^nd number) × 4

= (11× 9) × 4

= 99 × 4

= 396 = 3^rd Number

Option (4) (7, 5, 78)

(1^st Number × 2^nd number) × 4

= (7 × 5) × 4

= 35 × 4

= 140 ≠ 3^rd Number

Hence, the correct answer is "(11, 9, 396)".