Wednesday, June 22, 2016

CBSE Class 9 - Chemistry - CH2 - Is Matter Around Us Pure? (Short Q and A)

Is Matter Around us pure?

Short Q & A

CBSE Class 9 - Chemistry - CH2 - Is Matter Around Us Pure? (Short Q and A)
Simple Distillation Technique.
Can you name the labelled parts? See answer at wikimedia


Q1: Who was the first scientist to use the term 'element'?

Answer: Robert Boyle was the first scientist to use the term element in 1661.


Q2: Name the chemist who for the first time, defined an element as a basic form of matter that cannot be broken down into simpler substances by chemical reactions.

Answer: Antoine Laurent Lavoisier (1743-94), a French chemist


Q3: Who is known as the father of Modern Chemistry?

Answer: Antoine Laurent Lavoisier (1743-94), a French chemist


Q4: Do physical changes alter the identity of a substance?

Answer: No.


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Wednesday, June 15, 2016

Class 8 - Maths - Algebraic Expressions and Identities (NCERT Ex 9.2 Answers)

Algebraic Expressions and Identities 


(NCERT Ex 9.2 Answers)


Class 8 - Maths - Algebraic Expressions and Identities (NCERT Ex 9.2 Answers)

Q1: Find the product of following pair of monomials.

(i) 4 , 7p


Answer:

4   ☓   7p = 4  ☓ 7   ☓ p = 28p

(ii) -4p , 7p

Answer:

-4p   ☓   7p = -4 ☓ p ☓ 7  ☓ p = (-4☓7)☓ (p☓ p) = -28p2

(iii) 4p , 7pq

Answer:

-4p  &#9747 7p = -4 ☓ p ☓7  ☓ p  ☓ q = (-4☓ 7)☓ (p☓ p☓ q) = -28p2q

(iv) 4p3 , -3p

Answer:

4p3  ☓  -3p = 4  ☓(-3)   ☓ p ☓ p☓ p☓ p = -12p4

(v) 4p , 0

Answer:

4p ☓ 0 = 4☓ p☓ 0 = 0


Q2: Find the areas of rectangles with the following pairs of monomials as their lengths
and breadths respectively.

(p , q);(10m , 5n);(20x2 , 5y2);(4x , 3x2);(3mn ,4np)


Answer:

We know that,

Area of rectangle = Length ☓ Breadth

Area of 1st rectangle = p ☓ q = pq

Area of 2nd rectangle = 10m ☓ 5n = 10☓ 5 ☓ m ☓ n = 50mn

Area of 3rd rectangle = 20x2 ☓ 5y2 = 20☓ 5 ☓ x2 ☓ y2 = 100x2y2

Area of 4th rectangle = 4x ☓ 3x2 = 4☓3 ☓ x ☓ x2 = 12x3

Area of 5th rectangle = 3mn ☓4np = 3☓ 4 ☓ m ☓ n ☓ n ☓ p = 12mn2p


Q3: Complete the table of products.

First Monomial (⇨)
Second Monomial(⇩)
2x -5y 3x2 -4xy 7x2y -9x2y2

2x 4x2 ... ... ... ... ...
-5y ... ... -15x2y ... ... ...
3x2 ... ... ... ... ... ...
-4xy ... ... ... ... ... ...
7x2y ... ... ... ... ... ...
-9x2y2 ... ... ... ... ... ...


Answer:

Monday, June 6, 2016

CBSE Class 10 - Science - CH7: Control and Coordination (VSQA)

CONTROL AND COORDINATION

CBSE Class 10 - Science - CH7: Control and Coordination (VSQA)

Very Short Question And Answers



Q1: Which chemical induces artificial ripening of fruits?

Answer: Ethylene


Q2: What is stimulus?

Answer: The changes in the environment to which an organism responds and reacts is called stimulus.


Q3: Name the longest cell present in the human body.

Answer: Neuron is the longest cell in the human body.


Q4: Give examples of glands which act as both endocrine and exocrine.

Answer: Pancreas, Testes, Ovaries


Q5: What are nastic movements?

Answer: Movements of plants which are independent of stimuli are called nastic movements. e.g. movement by Touch-Me-Not (Mimosa) plant i.e. leaves close or droop when touched.


Q6: Where do you find gustatory receptors?

Answer: On the tongue.


Q7: What do olfactory receptors detect?

Answer: They detect smell.


Q8: Name the hormone released by thyroid gland.

Answer: Thyroxin.


Q9: Where is Hypothalmus is located?

Answer: In the brain.

Sunday, June 5, 2016

Class (6 - 12) English Grammar - KINDS OF SENTENCES (Part 1)

KINDS OF SENTENCES (Part 1)

Class (6 - 12) English Grammar - KINDS OF SENTENCES (Part 1)

Sentences based on functions are categorised as follows:

1. Assertive Sentences
2. Interrogative Sentences
3. Imperative Sentences
4. Optative Sentences
5. Exclamatory Sentences

Assertive Sentences

These sentences merely assert an incident or a fact.
e.g.
The sun is a big star. (Affirmative)
The Taj is a beautiful monument.         (Affirmative)
He is not in Delhi. (Negative)
It does not glow at night.         (Negative)

Sentences that affirm one or the other fact are called affirmative sentences. First two sentences listed above are affirmative ones.

Sentences that negate a fact are called negative sentences. The last two sentences listed above are negative sentences.

Exercise:
Convert the following affirmative sentences into negative sentences.

1. I like him.
2. Banana is a sweet fruit.
3. They play for Delhi Soccer club.
4. We sing a song.
5. He gets up early.


Answers:
1. I do not like him.
2. Banana is not a sweet fruit.
3. They do not play for Delhi Soccer club.
4. We do not sing a song.
5. He does not get up early.


Sunday, May 29, 2016

CBSE Class 9 -12: English Grammar Quiz

ENGLISH GRAMMAR QUIZ
CBSE Class 9 -12: English Grammar Quiz

[Questions from SSC Exam Paper 2014]
Q (1 - 5) In these questions some part of the sentences have errors and some are correct.Find out which part of the sentence has error and mark that part (A), (B) or (C). If a sentence is free from error, then mark (D) as your answer.


Q1: In his book (A)/ Churchill describes (B)/ that historical first meeting with Roosevelt (C)/ No error (D).

Q2: The ant who was nearby (A) / walked forward and bit the hunter (B)/ sharply in the ankle (C) / No error (D).


Q3: They can promise you (A) / an experience (B) / you won't never forget (C)/ No error (D)


Q4: The dress that the (A) / girl wore was (B)/ more attractive than the other girls (C)/ No error (D)


Q5: Fifty years has passed (A)/ since man first ventured (B)/ in outer space (C)/ No error (D).


Directions (6 - 10): Fill up the blanks with approproate word(s) in the sentences. Four options are given, choose the correct one. 


Q6: I can ______ him without qualifications.

(a) recommend
(b) commend
(c) praise
(d) suggest


Q7: She let her horse ________ in the field.

(a) loosen
(b) loose
(c) loosely
(d) lose

Tuesday, May 17, 2016

Class 12 - Physics - Chapter 4: Moving Charges and Magnetism (VSQA)

Moving Charges and Magnetism

Very Short Q & A

Class 12 - Physics - Chapter 4: Moving Charges and Magnetism (VSQA)

Q1: Define Magnetic Field.

Answer: The space around a magnet within which its effect is experienced is called Magnetic Field (B).


Q2: What is the SI unit of magnetic field?

Answer: Tesla. Another unit is Newton Ampere-1 metre-1


Q3: What is a solenoid?

Answer: A solenoid is a circular coil of a large number of turns, such that the turns of solenoid run parallel to its length. It acts similar to a bar magnet.


Q4: What is Lorentz force?

Answer: The total force on a charge (q) moving with a velocity (v) in the presence of magnetic and electric field (B and F) respectively is called Lorentz force.


Q5: What is a cyclotron?

Answer: It is a machine to accelerate charged particles or ions to high energies


Q6: What is the operational definition of one ampere?

Friday, May 13, 2016

CBSE Class 8 - Science - METALS and NON Metals : Question and Answers

METALS and NON Metals : 
Question and Answers

Prachi Class 8 Science Textbook Solutions

CBSE Class 8 - Science - METALS and NON Metals : Question and Answers
Activity Series


Q1: Identify the type of elements which are neither malleable nor ductile.

Answer: Non-metals (eg Carbon, Phosphorous, Sulphur, Nitrogen) are neither malleable nor ductile.


Q2: Name a property which is common to the metals occurring near the bottom of the reactivity series.

Answer: These (Silver, Gold and Platinum) are least reactive metals and are found in free state in the earth's crust.


Q3: Name a metal that is kept under kerosene.

Answer: Sodium.


Q4: What type of reaction is the reaction between copper sulphate solution and zinc plate?

Answer: It is a displacement reaction.
        Zn + Copper Sulphate ---------> Zinc Sulphate + Copper

(Explanation: Zinc is more reactive than copper, Therefore Zn displaces Cu.)



Q5: An oxide of sulphur turns blue litmus red. Is it acidic or basic?

Answer: Acidic