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.