Question Discussion & Solution

Concept:

• Force: Force is a push or pull on an object. A force can cause an object to accelerate, slow down, remain in place, or change shape.

Force exerted = mass x acceleration

F = m × a

Acceleration = (Final velocity(v) - Initial velocity(u))/ time

\(a = \frac{{v - u}}{t}\)

Where F is the force exerted on the body, m is mass of the body, a is the acceleration of the body, v is final velocity, u is initial velocity and t s time.

Calculation:

Given,

Mass of body = 6 kg.

Change in velocity = (18 - 6) = 12 m/s

Time= 3 sec

Acceleration = 12/ 3 = 4m/s² 

Force = mass × acceleration

Force = 6 × 4 = 24 Newton.

Hence the correct option is 24 Newton

• The blue litmus paper will turn red when it comes into contact with an acidic solution.
• When a litmus paper is put in a solution, depending on what the solution is, the indicator will react with the solution and will change its colour.
• On the other hand, red litmus paper reacts to alkaline substances by turning blue.
• Note: Acid will turn red litmus paper to red only.No change.

Concept:

• Plants have different types of roots.
• Some store food, some breathe some hang from the branches.

Explanation:

• Roots are the underground structures that help in the absorption of water and minerals provide a proper anchorage to the plant parts, storage of reserve food material (Carrot, Radish), and synthesis of PGR (plant growth regulators).
• Sometimes roots get modified to perform different functions like storage of food, respiration, climbing, etc.
• These types of roots are called modified roots.
• Examples - prop root of the Banyan tree for providing support, Pneumatophores of Rhizophora, and Mangrove plants for respiration.

So, these statements are correct.

• To give support to the plant.
• To store food.
• To absorb water and minerals.

Thus, roots do not function to provide humus.

• In SQL, the function - avg, min, max, sum, count is called as aggregate function.
• Aggregate functions return a single value after calculating from a group of values.
• avg() function returns the average values, max() returns the maximum value, count() finds the number of rows that matches the specified condition, min() returns the minimum value, Max() returns the maximum value. sum() returns the sum of values.

Example:

SELECT AVG(salary

FROM employees

GROUP BY department_id;

The correct answer is Aravali.

• Aravali range forms the main water area for Rajasthan.

Key Points

• Aravali range​
  • The Aravallis of Northwestern India, one of the oldest fold mountains of the world, now form residual mountains with an elevation of 300m. to 900m.
  • They stretch for a distance of 800 km from Himmatnagar in Gujarat to Delhi, spanning Haryana, Rajasthan, Gujarat, and Delhi, the 692 kilometres (km).
  • The Aravallis act as a barrier between the fertile plains in the east and the sandy desert in the west.
  • Historically, it is said that the Aravalli range checked the spread of the Thar desert towards the Indo-Gangetic plains, serving as a catchment of rivers and plains.
  • Thus Aravali range forms the main water area for Rajasthan.

​Additional Information

•  Aravali range formation
  • ​These are fold mountains of which rocks are formed primarily of the folded crust when two convergent plates move towards each other by the process called orogenic movement.
  • The Aravallis date back to millions of years when a pre-Indian sub-continent collided with the mainland Eurasian Plate.
  • Carbon dating has shown that copper and other metals mined in the ranges date back to at least the 5th century BC.