CBSE Class 10- Chapter 11 - Human Eye and the Colourful World (Very short Q & A)

Human Eye and the Colourful World

Very Short Questions and Answers

Q1: Name a light sensitive part of the eye where image of an object is formed.
Answer: Retina

Q2: Name the muscle responsible for bringing change in the focal length of the eye lens ?
Answer: Ciliary Muscles

Q3: Name one defect of vision which cannot be corrected by any type of spectacle lenses ?
Answer: Cataract

Q4: What is the nature of image formed on the retina of the eye ?
Answer: Real and inverted image.

Q5: Name the transparent membrane through which light enters the eye.
Answer: Cornea

Q6: What type of signals are generated & sent to the brain by light sensitive cells of retina?
Answer: Elctro-chemical Nerve signals are generated by rods and cones (photo sensitive cells of retina) and are sent to brain by optic nerve.

CBSE Class 9 - Science - Chapter 10 - Floatation & Archimedes’ Principle

Floatation & Archimedes’ Principle

Italian Stamp in honour of Archimedes
credits: St. Andrews Univ

Chapter Notes, NCERT Q & A and Numerical Problems

1. The force acting per unit area of the object is known as pressure.

 The SI unit of Pressure is N/m² or Pascal (Pa)

2. Density or Mass density is the ratio of mass per unit volume.

The SI unit of density is kg/m³
A density of an object is a key factor that decides whether it’ll float or sink in a liquid.

Q3: The weight of a man is 690N which contains 5.3 x 10^-3 m³ of blood.
Find (a) blood's weight. Take density of blood is 1060 kg/m³
        (b) express it as a percentage of body weight.

Answer: (a) Since  m = ρ x V
and W = mg
∴ W = (ρV)g = 1060 x 5.3 x 10^-3  x 9.80
⇒ W = 54N

CBSE - Class 10 - Biology - Chapter 15 - Our Environment

Chapter: Our Environment

Q1: Define Ecology

Answer: Ecology is a scientific study of the interactions between organisms and the environment. Ecology integrates all areas of biological research and  informs environmental decision.

Q2: What is the scope of Ecology Research?

Answer: Ecology study can be broadly classified as:
           a. Organismal Ecology
           b. Population Ecology
           c. Community Ecology
           d. Ecosystem Ecology
           e. Landscape Ecology
           f. Global Ecology

In nutshell, Ecology study advocates protection of nature and the environment.

Q3: Define Ecosystem.

Answer: An environment comprises of all living (biotic) and non-living (abiotic) things that occur naturally on the Earth or any of its region. All these living organisms interact with each other and their growth, reproduction and other activities are affected by the abiotic components of ecosystem.

Q4: Is garden an example of Ecosystem?

Answer: Yes. In an garden, all biotic components (e.g. plants, trees, animals like rats, frogs, birds, insects etc.) interact with each other and with abiotic components (garden soil, water etc.) for their growth and reproduction and other activities. Thus garden forms an ecosystem.

Q5: Give examples of natural ecosystems.

Answer: Forests, ponds, lakes, sea, oceans, coral reefs, rivers etc.

Q6: Give examples of human made (artificial )ecosystems.

Answer: Gardens, Crop-fields etc.

CBSE Class9-Science 11 (Work, Power Energy) MCQ

Work, Power Energy

MCQs

Q1: An example of Kinetic energy would be:
a. a moving car
b. a charge particle in an electric field.
c. a stretched rubber band just released.
d. all of the above.

Q2: Newton-meter is the SI unit of 
a. acceleration
b. work
c. power
d. force

Q3: Which of the following is/are example(s) of Potential Energy
a. A moving car.
b. A battery
c. A book resting on the table
d. both b and c

NTSE SAT Quiz-7 (History)

Test your knowledge about Indian History. answer these simple 7 questions. Enter your name and email-id, and click on 'Start' button to start quiz. If you like it, do send me your comments, I will prepare more MCQs on suggested topics.

NTSE (SAT History) » Quiz maker software

Tips and Checklist before appearing for NTSE Stage-1 Examination

This Sunday, November 20, 2011 is all set for NTSE Stage 1 examination. You may get details about the NTSE examination from NCERT website.

Following are important Tips and  checklist before going for the test.

1. Photocopy your hall ticket for future reference. The original Hall Ticket is taken by the invigilators at the examination hall. Do not forget to bring your hall ticket other wise you will not be allowed to enter the hall.

2. Reach the examination center at least 45 minutes to 1 hour earlier.  Sometimes hustle and bustle occurs for finding the seats.

3. Most of the times, the examination venues chosen for NTSE examination are Government Schools. It might happen there are not proper desks and candidates have to sit on mats. You should bring your own card boards to write properly.

4. Carry 3-4 HB sharpened pencils, eraser, a sharpener and a pen. Don't forget to wear your wrist watch. Calculators in any form are not allowed.

Why do people, having skin problems, are advised not to wear violet or red clothes?

Q: Why do people, having skin problems, are advised not to wear violet clothes?

Answer: Violet  rays coming from the sun carry high energy. Once such radiation falls on the thin skin, it reacts immediately. It may aggravates the skin problem or might produce other side effects.

NTSE MAT Quiz-1 (Series completion)

Complete the following series:

1.  6,12,21,___,48,66
 (a) 33      (b) 38       (c) 40       (d) 45

2.  125,80,45,20,___
 (a)  5        (b)    8     (c) 10        (d)12

3.  22,24,28,___,52,84

 (a)  30        (b)   36      (c)    42     (d) 46

4. 1,3,3,7,6,13,10,___,15,31


(a)  25        (b)   27      (c)    21     (d) 30

5. 3,1,7,3,13,7,21,15,31,31,___,63,57


(a)    39      (b) 41        (c)  38       (d) 43

Hindi Synonyms Quiz ( पर्यायवाची प्रश्नोत्तरी)

पर्यायवाची प्रश्नोत्तरी                                                     

१.अद्भुत 
(क) अजीब ,अनोखा
(ख)  अनुपम,विचित्र
(ग) आश्चर्यजनक ,विलक्षण
(घ) अपूर्व,अलौकिक

२.अंक 
(क) संख्या,गोद
(ख) चिन्ह,लेख
(ग) धब्बा,पाप
(घ) गोद,निशान

३.अंचल 
(क) आँचल,छोर
(ख) सीमान्त,प्रान्त
(ग) तट,किनारा
(घ) सीमा ,भूभाग

NTSE SAT Quiz-7 (Maths)

Q1: The sides of a right triangle are a, a+d, a+2d with a and d both positive. What is the value of ratio a:d ?
(a) 1: 3
(b) 1:4
(c) 2:1
(d) 3:1

Q2: In a group of cows and hens, the number of legs was 14 more than twice the number of heads. the number of cows is:
(a) 5
(b) 7
(c) 12
(d) 14

Q3: Each edge of cube is increased by 50%. The percent increase in surface area of the cube will be:
(a) 50
(b) 125
(c) 150
(d) 300

CBSE Class 9 - Chapter 11- Physics - Work And Energy (Q and A)

Work & Energy (Q & A)

Q1: A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the
force. Let us take it that the force acts on the object through the displacement. What
is the work done in this case?

Answer:  Let F be the force acting on the object displacing it by distance S, in the same direction of the force.
∴  F = 7N   and S = 8m
Work done (W) = Force (F) × Displacement (S)

 = 7 x 8 = 56 Joules

Q2(NCERT): When do we say that work is done?

Answer: Work is said to be done when the following conditions are met:
        (i) a force acts on the body.
       (ii) A displacment of the body occurs by virtue of applied force in the direction of applied force.

Q3(NCERT): Define 1 J of work.

Answer: 1 J is the amount of work done by a force of 1 N on an object that displaces it through a distance of 1 m in the direction of the applied force.

Q4: Is Work a scalar or vector quantity?

Answer: Although work is product of two vectors, it is a scalar quantity.

Class 10 - Light Reflection and Refraction (Short Q & A)

Light Reflection and Refraction 

(Short Q & A)

Q1: In which type of lens linear magnification is always less then one?

Answer: Concave Lens always has linear magnification less than one, because it always gives diminished images.

Q2: John obtained a magnification of 1 with concave mirror of focal length 10cm. What is the object distance from mirror?

Answer: m = 1. Therefore u = v. Apply it in mirror formula, you will get v = 20 cm. 

Q3: Which mirror has a wider field of view?

Answer: convex mirrors have wilder field view, that's why these are used as rear view-mirrors in vehicles. 

Q4: Which is optically denser out of the two mediums M1 and M2 having n = 1.71 and 1.36
respectively.

Answer: M1 (it has higher value of refractive index).

Q5: Identify a mirror having focal length –15cm

Answer: concave mirror (see -ve sign of focal length).

NTSE SAT Quiz-6 (Geography)

Q1: Chilka is the name of:
   a. a lake in the eastern coast of India.
   b. the mountain in the Himalayas
   c. a river in Maharashtra
   d. an industrial town in Jharkhand.

Q2: Which Indian state tops in hosiery and woolen goods in India:
  a. Karnataka
  b. Bihar
  c. Punjab
  d. Maharashtra


Q3: Bhubaneswar, capital of Orissa is famous for its:
   a. Oil Refinery
   b. shipping industry
   c. space research centre
   d. famous lingaraja temple.

NTSE SAT Quiz-5 (Questions from HP NTSE SAT Paper)

Following questions appear in STSE SAT Paper.

Q.1 In which part of the body the most of iron is present?
1) Blood
2) Bones
3) Muscles
4) Heart

Q.2 Which is the pea shaped endocrine gland that is situated in the bony cavity at the base of the brain?
1) Thyroid
2) Pituitary
3) Adrenal glands
4) Thymus

Q.3 How many ovaries and fallopian tubes are there in a female body?
1) 2 ovaries and 2 fallopian tubes.
2) 2 ovaries and 1 fallopian tubes.
3) 2 ovaries and 4 fallopian tubes.
4) 4 ovaries and 2 fallopian tubes.

Class 8 - Science - Combustion and Flame (Q & A)

COMBUSTION AND FLAME 

(Questions and Answers)

Q1. What is the difference between the burning of a candle and the burning of fuel like coal?

Q2. Why a matchstick does not catch fire on its own at room temperature?

Answer: A substance does not catch fire until its temperature is raised to its ignition temperature. A matchstick, a piece of wood or a can full of kerosene do not catch fire on their own because the ignition temperature of these substances is higher that the room temperature (25 °C).

(Note: When we strike the match stick against the matchbox, because of friction its temperature rises to ignition temp. and it ignites.)

Q3. Akansha made two paper cups by folding a sheet of paper. She poured 50 ml of water into one of the cups and heated both the cups separately with a candle.
  a. What happens to the empty paper cup when it is heated?
  b. What happens to the paper cup with water?
  c. Does water in this cup becomes hot?

Q4. List out the names of some inflammable substances.
Answer: Petrol, Diesel, Alcohol, Kerosene

NTSE Maths Challenges

Following are the typical problems asked in NTSE, Oympiad Maths,  and other Mathematical based aptitude tests
(best viewed in Chrome or Firefox).

Q1: Ramesh walks from his home to Railway station at the rate of 5 kmph, he misses the train by 7 minutes. However, if he walks at the rate of 6 kmph, he reaches the station 5 minutes before the arrival of the train. Find the distance of the station from his home.

Answer: Let 'd' be the distance between Ramesh's house to Station.
We know that distance = speed x time.

If he walks at speed 5 kmph, let time taken be t1
⇒ t1 = d/5

Let the time t2 is taken when he walks with a speed of 6 kmph.

⇒  t2 = d/6

Since the time gap between two cases is 12 mins = 1/5 hrs
⇒ t1 - t2 = d/5 - d/6 = 1/5 hrs
⇒  6d - 5d = 6
⇒ d = 6km

Q2: Roma travels from place A to B and then from B to C.
From A to B Distance is 55 km which she covers with an average speed of 22 km per hour
It takes her 1 hour 30 minutes moving from B to C with an average speed 30 km per hour
Calculate her average speed over the whole of her journey from A to C.

Answer: We know that $ Time = Distance ÷ Speed

∴ Time taken from A to B = 55/22 = 2.5 hours  = 2 Hrs and 30 mins

Distance from A to B = Speed x Time = 20 x 1.5  = 45 km.  (note time taken from B to C is given as 1 Hrs 30 minutes i.e. 1.5 Hrs)

Average Speed = Total Distance  ÷ Total Time
∴  = (55+45) ÷ (1.5+2.5) = 100  ÷ 4 = 25 kmph

CBSE Class 10 - English Workbook Solutions (Unit 12 Active Passive)

CBSE Class 10 - English Workbook Solutions 2011 (Unit 12 - Active and Passive)

Answer 1: 
1. are employed (passive)
2. Did anybody/somebody clean
3. is covered
4. are locked
5. was sent, arrived
6. were these photographs taken, Did you take

Different types of constructions are used in above sentences i.e. active and passive. In active voice, the person or thing who is responsible for the action comes first. In passive, the person or thing acted on comes first and the actor is generally added in the end by preposition 'by'.

Answer 2: (clue Finding)
1. The enemy killed him. It is obvious from the passive sentence "He was killed in the World War II".
2. It is understood that robbers looted the bank, but the stress should be on "the bank".
3. The fans/admirers who look upon Sachin Tendulkar as sporting icon, are least important.

4. People can see this sort of raod-side restaurants everywhere in this city.
5. The police arrested him when he arrived at the airport. Yes the active voice is little awkward because everybody knows it is the police who arrests people.
6. Active Voice: The company will pay bonus because of handsome profits.
7. Passive Voice: 'I got' means 'I've got'. Generally 'have' is not written along with got.

Answer 3: Match the following...
a. Newspaper and formal report - (3) Many villagers were ...
b. Description of processes - (1) The tea leaves are picked ...
c.  Academic writings including reporting of ....  - (2)  20 ml of the salt ...

NTSE SAT Quiz-4 (Books and Authors)

Q1. "Discovery of India" is
   a. a biography of Mahatma Gandhi
   b. an autobiography of Jawah Lal Nehru
   c. a biography of Indira Gandhi
   d. history book written by Jawahar Lal Nehru

Q2: Who wrote 'Artha Shastra'?
   a. Kautaliya
   b. Banbhatt
   c. Vatsayan
   d. Vagabhatt

Q3: Panchtantra was written by
   a. Ved Vyas
   b. Valmiki
   c. Vishnu Sharma
   d. Tulsidas

Q4: Meghdoot was authored by
   a. Kalidas
   b. Banbhatt
   c. Vishnu Dutt
   d. Kabirdas

Q5: Who is the author the book "Origin of Species"?
    a. Karl Mark
    b. Thomas Edison
    c. Charles Darwin
    d. Leo Tolstoy

Q6: Who wrote "Rajtarangini"?
   a. Kalhana
   b. Kalidas
   c. Charak
   d. Harshvardhan

Class 10 - Chapter 4- Carbon and its Compunds (Short Questions & Answers)

Class 10 - Chapter 4- Carbon and its Compounds

Methane Structure

(Short Questions & Answers)

Q1: State whether the following are true or false
       a. Both alkenes and cyclo-alkanes both can be represented by the same general formula.
       b. The general formula C_nH_2n is valid for any alkene with any number of multiple bonds,
       c. Acetone is the common name of propanone.
       d. Isomers always show same chemical properties.


Q2: Which is the common name for ethyne?

Q3: The complete combustion of a hydrocarbon always gives .....?

Q4: What is the term used for the compounds which have same molecular formula but
       different structures?

NTSE (SAT Quiz-3)

Q1: Which of the following is an antibiotic?
       a. Aspirin
       b. Penicillin
       c. Paracetamol
       d. Sulphadizine

Q2: Digestion of food starts in:
       a. mouth
       b. liver
       c. stomach
       d. intestines

Q3: By taking the pulse rate of the human body, a doctor determines
       a. heartbeat
       b. functioning of heart valves
       c. condition of lever
       d. functioning of lungs

Q4: A thermostat is used to
       a. purify air
       b. regulate humidity
       c. regulate temperature
       d. regulate air pressure

Q5: Heat from the sun reaches the earth by
        a. reflection
        b. conduction
        c. convection
        d. radiation

Q6: Dew forms most readily on nights that are:
        a. calm and clear
        b. stormy
        c. windy
        d. cloudy

Q7: The full moon rises in the
        a. east
        b. west
        c. south
        d. north

Q8: An aeroplane is able to fly because
       a. it is lighter than air
       b. it is heavier than air
       c. it is made up of very light material
       d. moving air can lift objects

Q9: The souring of milk is caused by the action of
        a. protozoan
        b. bacteria
        c. virus
        d. fungus

Q10. The smallest thing that can cause disease in the human body is
         a. flea
         b. bacteria
         c. protozoa
         d. virus

Q11: The most abundant gas in the air is:
         a. oxygen
         b. carbon dioxide
         c. nitrogen
         d. hydrogen

Q12: Which element is common between brass and bronze
         a. copper
         b. Iron
         c. Zinc
         d. Aluminium

Q13: The densest element known so far is
         a. gold
         b. mercury
         c. osmium
         d. tungsten

Q14: The most ductile element is
         a. gold
         b. silver
         c. iron
         d. aluminium

Q15: The metal having the highest melting point is
         a. chromium
         b. tungsten
         c. diamond
         d. Silver

Answers: 1-b     2-a     3-a     4-c    5-d     6-a     7-a    8-d    9-b    10-d

                11-c    12-a   13-c    14-a   15-b

See other quizes at link1, link2, link3

Chemical Formula for daily use material

Following is the list of substances of daily use and their chemical formula. It is seen there is always a question in NTSE asking chemical formula of daily use material.

Chemical Formula for daily used substances

Compound Name	Formula	Uses
Acetaminophen	C8H9NO2	pain reliever
Acetic acid	C2H4O2	tart ingredient in vinegar
Ammonia	NH3	fertilizer, household cleaner when dissolved in water
Ascorbic acid	C6H8O6	vitamin C
Aspirin	C9H8O4	pain reliever
Baking soda	NaHCO3	cooking
Caffeine	C8H10N4O2	the stimulant in coffee, tea, some soda
Calcium carbonate	CaCO3	antacid
Carbon dioxide	CO2	carbonating agent in soda
Ethanol	C2H5OH	disinfectant, alcoholic beverages
Ethylene glycol	C2H6O2	antifreeze
Hydrochloric acid	HCl	called muriatic acid, cleans mortar from brick
Magnesium hydroxide	Mg(OH)2	antacid
Methane	CH4	natural gas, fuel (also called Marsh Gas)
Phosphoric acid	H3PO4	flavouring in soda
Potassium tartrate	K2C4H4O6	cream of tartar, cooking
Propane	C3H8	fuel for cooking
Sodium Chloride	NaCl	flavouring (table salt), freezing
Sodium carbonate	Na2CO3	washing soda
Sodium hydroxide	NaOH	drain cleaner
Sucrose	C12H22O11	sweetener
Sulfuric acid	H2SO4	battery acid
Water	H2O	washing, cooking, cleaning
Water gas	H2 + CO	heating and lighting
Gypsum	CaSO4.H2O	plaster of paris

Another list is also posted on the wiki.