Question Discussion & Solution

Given: Victory ∶ Encouragement ∶∶ Failure ∶ ?

Logic:

Victory leads to Encouragement.

Similarly,

Failure leads to Frustration.

Hence, frustration is the correct answer.

CONCEPT:

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

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

EXPLANATION:

• Both Dyne and Newton are units of force in the CGS and S.I system.
• Newton and dyne can also be written as (1 N = kg-m/s2) and (1 dyne = gm-cm/s2).
• The relation between the Newton and  Dyne is given as 

⇒ 1 N = 105 dyne

• Therefore, the ratio of SI unit and CGS unit of force is

\(\Rightarrow \frac{N}{Dyne} = 10^5\)

Valency is the combining power of an element. Elements in the same group of the periodic table have the same valency.

Key Points

• Valency is the no of electron that looses, shared or gain to achieve stability or we can say to complete it outer most shell. 
• If any element has valence electron (electrons present in outer most shell) less than 4
  • ​​Valency = no of valance electron (valence electron<4)
• If any element has valence electron ​more than 4
  • ​​Valency = 8 - no of valance electron (valence electron>4)

​For Lithium:

• Li(Z=3) Electronic configuration = 2, 1
  • Valency = no of valance electron  = 1

​Hence, we can conclude that 1 is the valency of Lithium.

Explanation:

• Sound is a longitudinal mechanical wave that propagates by making compressions (high pressure) and rarefactions(low pressure) in its propagating medium. 

• The amplitude of wavelength is the maximum distance the particle oscillating moves from the mean position.
• The frequency of the wave is the number of times one complete cycle of compressions 

• More the frequency more is the pitch of the sound, the sound is having more shrillness. 
• The more the amplitude the more is the loudness of the sound. 

So, loudness depends upon the amplitude.

Important Points 

• The Pitch of the sound depends upon frequency. 
• Mathematically, loudness is directly proportional to the square of the amplitude. 

L ∝ A2

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.