Science & Technology (Part I) - Acche Marks

Answer the following with explain: ₃Li, ₁₄Si, ₂He, ₁₁Na, ₁₅P, Which of these elements belong to be period 3? Also write down the electronic configuration of the following elements from the given atomic numbers.

February 4, 2024 by Acche Marks

An element has its electron configuration as 2,8,2. Now answer the following questions.

February 4, 2024 by Acche Marks

1. What is the atomic number of this element? Answer: 2. What is the group of this element? Answer: 3. To which period does this element belong? Answer: 4. With which of the following elements would this element resemble? (Atomic numbers are given in the brackets) N (7), Be (4) , Ar (18), Cl (17) … Read more

Take weights of five of your friends. Find out what their weights will be on the moon and the Mars.

February 4, 2024 by Acche Marks

The mass of the earth is 6 x 1024 kg. The distance between the earth and the Sun is 1.5x 1011 m. If the gravitational force between the two is 3.5 x 1022 N, what is the mass of the Sun? (Use G = 6.7 x 10-11 N m2 kg-2)

February 4, 2024 by Acche Marks

Ans: 1.96 x 1030 kg

The masses of the earth and moon are 6 x 1024 kg and 7.4×1022 kg, respectively. The distance between them is 3.84 x 105 km. Calculate the gravitational force of attraction between the two? (Use G = 6.7 x 10-11 N m2 kg-2)

February 4, 2024 by Acche Marks

Ans: 2 x 1020 N

A ball falls off a table and reaches the ground in 1 s. Assuming g = 10 m/s2 , calculate its speed on reaching the ground and the height of the table.

February 4, 2024 by Acche Marks

Ans. 10 m/s and 5 m

An object thrown vertically upwards reaches a height of 500 m. What was its initial velocity? How long will the object take to come back to the earth? Assume g = 10 m/s2

February 4, 2024 by Acche Marks

Ans: 100 m/s and 20 s

The mass and weight of an object on earth are 5 kg and 49 N respectively. What will be their values on the moon? Assume that the acceleration due to gravity on the moon is 1/6th of that on the earth.

February 4, 2024 by Acche Marks

Ans: 5 kg and 8.17 N

The radius of planet A is half the radius of planet B. If the mass of A is MA, what must be the mass of B so that the value of g on B is half that of its value on A?

February 4, 2024 by Acche Marks

Ans: 2 MA

An object takes 5 s to reach the ground from a height of 5 m on a planet. What is the value of g on the planet?

February 4, 2024 by Acche Marks

Ans: 0.4 m/s2