Explain various Access Modifiers in Java.

Which gas is usually liberated when an acid reacts with a metal? Explain with a suitable example. 

What are the factors which influence the adsorption of a gas on a solid?

Distinguish between the meaning of the terms adsorption and absorption. Give one example of each.

What is the role of desorption in the process of catalysis?

An organisation selected 2400 families at random and surveyed them to determine a relationship between income level and the number of vehicles in a family. The information gathered is listed in the table below.

1500 families with two children are selected randomly according to the data given below.

Compute the probability of a family, chosen at random, having
(i) 2 girls
(ii) 1 girl
(iii) no girl
Also, check whether the sum of these probabilities is 1.

In a cricket match, a batsman hits a boundary 6 times out of 30 balls she plays. Find the probability that she did not hit a boundary.

Why did a major protest erupt in 1926 in the Saigon Native Girls School in Vietnam ? Explain.

To counter the Chinese influence what steps did the French take in the sphere of education? What were the two broad opinions on this question?

Describe the ideas behind the Tonkin Free School. To what extent was it a typical example of colonial ideas in Vietnam ? [CBSE 2009 (F), 2013 (O)]

Write a note on
(a) What was meant by the ‘civilizing mission’ of the colonisers?
(b) Huynh Phu So.

The houses of a row are numbered consecutively from 1 to 49. Show that there is a value of x such that the sum of the numbers of the houses preceding the house numbered x is equal to the sum of the numbers of the houses following it. Find this value of x. [Hint : S_x-1 = S₄₉ – S_x ]

Ramkali saved Rs 5 in the first week of a year and then increased her weekly saving by Rs 1.75. If in the nth week, fher weekly savings become Rs 20.75, find n.

Which term of the AP: 21, 18, 15, . . . is – 81? Also, is any term 0? Give reason for your answer.

The sum of the third and the seventh terms of an AP is 6 and their product is 8. Find the sum of the first sixteen terms of the AP.

A sum of Rs 700 is to be used to give seven cash prizes to students of a school for their overall academic performance. If each prize is Rs 20 less than its preceding prize, find the value of each of the prizes.

Q. 1 If the sum of the first n terms of an AP is 4n − n², what is the first term (that is S₁)? What is the sum of first two terms? What is the second term? Similarly find the 3rd, the 10th and the nth terms.

Q. 2 Check whether – 150 is a term of the AP: 11, 8, 5, 2 . . .

The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.

The sum of 4th and 8th terms of an A.P. is 24 and the sum of the 6th and 10th terms is 44. Find the first three terms of the A.P.

Write first four terms of the A.P. when the first term a and the common difference d are given as follows:

(i) a = 10, d = 10
(ii) a = –2, d = 0
(iii) a = 4, d = – 3

Draw a plot of α-particle scattering by a thin foil of gold to show the variation of the number of the scattered particles with scattering angle. Describe briefly how the large angle scattering explains the existence of the nucleus inside the atom, Explain with the help of impact parameter picture, how Rutherford scattering serves a powerful way to determine an upper limit on the size of the nucleus.

A long solenoid with 15 turns per cm has a small loop of area 2 cubic cm placed inside the solenoid to its axis. If the current carried by the solenoid changes steadily from 2 Ampere to 4 Ampere in 0.1 second. What is the induced emf in the loop while the current is changing.

What does an Electrical Circuit Mean? Define the unit of current. What is the definition of an electrical current. Also write some other units which you know.

Find the roots of the given quadratic equation
1. (x + 1)² = 2(x – 3)
2. 100 x² – 20x + 1 = 0

(a) Define olfactory indicators. Name two subtances which can be used as olfactory indicator.
(b) Choose strong acids from the following:
CH₃COOH, H₂SO4, H₂CO₃, HNO₃

Define parallel connection and series connection?

What are polyatomic ions? Give examples?

Calculate the molecular masses of the following elements

• H₂
• O₂
• Cl₂
• CO₂
• CH₄
• C₂H₆
• C₂H₄
• NH₃
• CH₃OH

Differentiate between homogeneous and heterogeneous mixtures with examples. List the points of differences between homogeneous and heterogeneous mixtures. 

How soil is formed?

How is our atmosphere different from the atmospheres on Venus and Mars?

When will you say a body is in Uniform acceleration and non-uniform acceleration?

Distinguish between speed and velocity.

Explain Atomic number, Mass number, Isotopes and Isobars with some examples. Also give any two uses of isotopes.

Write the distribution of electrons in carbon and sodium atoms. Explain in details.

How will you find the valency of chlorine, Sulphur, and magnesium? Explain with some examples.

What are canal rays? Why anode rays are called canal rays. Mention two postulates of J.J. Thomsons Model.