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Showing posts with label class10-physics. Show all posts
Showing posts with label class10-physics. Show all posts

Sunday 7 October 2018

CBSE Class 12 - 9 - How Good Your are in Physics? - Simple Physics Quiz (1 Word Answers)(#cbsenotes)(#eduvictors)(#physicsquiz)

Q1: Who firstly demonstrated experimentally the existence of electromagnetic wave?

Q2: The working of the quartz crystal in the watch is based on which effect?

Q3: What is the unit of Radioactivity?

Q4: What is the wavelength of the visible spectrum?

Q5: One astronomical unit is the average distance between___?

Q6: Number of basic S.I. units are ___.

Q7: What is the name of the scientist who stated that matter can be converted into energy?

Q8: The size of the atomic nucleus is of the order of___?

Q9: A temperature at which both the Fahrenheit and the centigrade scales have the same value?

Friday 5 October 2018

CBSE Class 10 - Science - Chapter 14 - Sources Of Energy - Study Points (#eduvictors)(#cbsenotes)

Class 10 - Science - Chapter 14

Sources Of Energy

Study Points

Energy:
Whenever a body is capable of doing work, the body is said to possess energy. Thus energy is defined as the ability of a body to do work and the amount of energy possessed by a body is equal to the amount of work it can do when its energy is released.

Energy comes in different forms and one form can be converted to another. For example, if we drop a plate from a height, the potential energy of the plate is converted mostly to sound energy when it hits the ground.

A good source of energy should be:

i) Safe and convenient to use, e.g., nuclear energy can be used only by highly trained engineers with the help of nuclear power plants. It cannot be used for our household purposed.

ii) Easy to transport, e.g., coal, petrol, diesel, LPG etc. Have to be transported from the places of their production to the consumers.

iii) Easy to store, e.g., huge storage tanks are required to store petrol, diesel, LPG etc.

Electricity - Assignment Sheet

Very Short Q & A (1 marks each)

Q1: Define resistivity of material.

Q2: What is the power of torch bulb rated at 2.5V and 500mA?

Q3: Why series arrangement not used for connecting domestic electrical appliances in a circuit?

Q4: Which has higher resistance – a 50W bulb or a 2.5W bulb and how many times?

Q5: What is the direction of flow of conventional current?

Q6: Calculate the amount of charge flowing in a wire if it draws a current of 2A in 10 minutes

Q7: What happens to resistance of a conductor if area of cross-section is doubled?

Q8: Which device helps to maintain a potential difference across a conductor?

Q9: Find the number of electron in 1C of charge.

Q10: Name the physical quantity whose unit is V/A.

Q11: Name the device that helps to maintain a potential a potential difference across a conductor.

The Human Eye and the Colourful World – Unit Test Paper

Q1: A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power which type?

Q2: Give reasons for the following:
i. Stars twinkle at night.
ii. The sun appears reddish early in morning.
iii. Planets do not twinkle.
iv. Red colour is used in danger signals.

Q3: A person walking in desert gets a illusion of seeing water. Name the phenomenon of light responsible for it.

Q4: Distinguish between Refraction and Dispersion.

Physics - Refraction From Lens

Q1: In refraction of light, what does Snell's Law state?

Answer: The ratio of sine of angle of incidence to the sine of angle of refraction remains constant subject to certain conditions. This is called refraction.

Q2: Which of the following property of light wave changes when it travels from one medium to another (having different optical densities)?

a. Wavelength
b. Speed of Light
c. Frequency

What is Total Internal Reflection?

① When a ray of light travels from optically denser medium to optically rarer medium, it bends away from the normal at the surface separating two media.

Science – Light, Refraction and Dispersion - Assignment

Q1: What do you mean by refraction of light? In which direction will light bend when travelling from an optically rarer medium to an optically denser medium?

Q2: Name the part of the eye which gives colour to the eyes.

Q3: Boojho while waving his hand very fast in front of his eyes, observes that his fingers appear blurred. What could be the reason for it?

Q4: How many times is a ray of light reflected by two plane mirrors placed parallel and facing each other?

Light and Reflection - Magnification Chart For Mirrors

Q: What is Magnification?

Answer: The ratio of height of image to the height of an object is known as magnification of an image and is denoted as m.

```           Image height         h'     -v
m = -------------------- = ---- = ----
Object height        h       u

```

The +ve value of magnification represents virtual image of an object.

The -ve value of magnification represents real image of an object.

Q: Using magnification formula, prove that image formed by a plane mirror is at the same distance as object but behind the mirror. It is given that in plane mirror, object height and image height are equal.

Light - Reflection From Mirrors (Worksheet)

1. We get a diminished image with a concave mirror when the object is placed ____.

2. The drivers mirror used in automobiles is ____.

3. The distance of focus F from the pole P is termed as the ..................... of the mirror.

4. Mirror formula is ____.

Electricity - (Holiday Assignment)

Q1: Two metallic wires A and B of same material are connected in parallel. Wire A has length l and radius r and wire B has length 2l and radius 2r. Compare the ratio of the total resistance of parallel combination and the resistance of wire A.

Wire A:
Length = l
Area   = πr²
R₁   = ρ  x l /(πr²)

Wire B:
Length = 2l
Area = π(2r)² = 4πr²
R₂   = ρ  x 2l /(4πr²) = ρ  x l /(2πr²)

Let Rₚ = effective resistance of parallel combination
1/Rₚ = 1/R₁ + 1/R₂

1/Rₚ = (πr²)/ρl + (2πr²)/ρl

Rₚ = ρl/(3πr²)

Sources of Energy (Important Differences)

Fossil Fuels Energy vs Solar Energy

Fossil Fuels Energy Solar Energy
1. Fossil energy can be used day or night. Can be used in day time. We need to store its energy to use it at night.
2. The stock of fossil energy is limited. e.g. coals will last for next 200 years. Sun’s energy is unlimited.
3. Fossil energy is non-renewable. It takes millions of year to produce fossil fuel. Solar energy is renewable source of energy.
4. Give pollution. Pollution Less
5. Fossil fuels release energy when they are burnt in air. Solar radiation carry packets of energy due to fusion reaction in the sun.

Electricity - Important Points To Remember

CBSE Class 10 - Physics

Electric current is defined as the amount of charge flowing through a particular cross section area in a unit time.

The SI unit of electric current is ampere.

A stream of electrons moving through a conductor constitutes an electric current. In a conventional current, the direction of current is taken opposite to the direction of flow of electrons i.e. flow of positive charges from +ve terminal to -ve terminal.

1 A is the flow of 6.25 × 10¹⁸ electrons per second, or 1 coulomb per second.

Electricity

Worksheet

Fill in the blanks

1. The source of all electricity is ______. It’s SI unit is _________.

2. The net charge flowing through a cross section of a conductor in unit time is called ________.

3. Electric potential difference between points in an electric circuit is the ______ _______ to move a unit charge from one point to other. i.e. 1V = ____/1C.

4. Current is measured in Amperes using _______.

5. If 90 coulombs charge passes through the conductor for 5 minutes, then the current in the conductor is _____.

6. A _________ is an electronic measuring instrument the combines several measuring functions (electric potential difference, electric current and electric resistance) in one unit.

Reflection of Light By Plane and Spherical Mirrors

 Laughing Mirrors use combination of Spherical Mirrors and Plane Mirrors. Is this image real or virtual?

Very Short Question Answers (Based on NCERT Chapter)

Q1: What is the position of the object, when we get a diminished image with a concave mirror?

Answer: Beyond C (centre of curvature)

Q2: What are Marginal rays?

Answer: The rays which strike the mirror surface near the periphery are called marginal rays.

Q3: What type of rear mirrors are used by drivers in automobiles?

Q4: What is the relation between the radius of curvature (R) and focal length (f) of a concave mirror?

Q5: What is a focal length in case of spherical mirrors?

Answer: It is the distance between focal length and focus.

Q6: An object is moving with a speed v towards a plane mirror, what is the speed of the image?

Sunday 27 October 2013

CBSE Class 10 - Science - Ch 11 - The Human Eye and the Colourful World (MCQs)

The Human Eye and the Colourful World
 Dispersion of Light Which light bends the most? credits:wpclipart
(MCQs)

Q1: By which optical phenomenon, the splitting of white light into seven constituent colours occur?
(a) Refraction
(b) Reflection
(c) Dispersion
(d) Interference

Q2: A human eye can focus on objects at different distances by adjusting the focal length of the eye lens. This phenomenon is due to:

(a) near sightedness
(b) long sightedness
(c) accomodation
(d) persistence of vision

*Q3: Which of the following are the primary colours?
(a) Red, Blue, Yellow
(b) Red, Green, Violet.
(c) Yellow, Green Blue
(d) Red, Green, Blue

Q4(NCERT): The human eye forms the image of an object at its
(a) cornea
(b) iris
(c) pupil
(d) retina

Friday 26 July 2013

Class 10 - Science - CH13 - Magnetic Effects of Electric Current (MCQs)

Magnetic Effects of Electric Current
 Magnetic field in wire loop credits:openclipart

MCQs

Q1: Inside the magnet the field lines run

(a) From south to north
(b) Away from north pole
(c) From north to south
(d) Away from the south pole

Q2: An electric charge in uniform motion produces:

(a) an electric field only
(b) a magnetic field only
(c) both electric and magnetic fields
(d) no such field at all

Q3: The magnetic field inside the solenoid is

(a) Non uniform
(b)Variable
(c) same at all points
(d) zero

Monday 25 March 2013

CBSE Class 10 - CH 12 - Electricity (MCQs)

Electricity
 An electric circuit

MCQs

Q1: The SI unit of electric charge is __________

(a) volts (V)
(b) ampere (A)
(c) coulomb (C)
(d) tesla (T)

Q2: By convention, the charge on a glass rod that has been rubbed with silk is called

(a) Positive
(b) Negative
(c) either positive or negative
(d) none of these

Q3: Two charged bodies having equal potential are connected through a conducting wire, in this case

(a) current will flow
(b) current will not flow
(c) cannot say
(d) current will flow if a resistor is also connected.

Friday 11 January 2013

CBSE Class 10 - Science - CH 16 - Management of Natural Resources (Q and A)

Management of Natural Resources
 Why do we need to use our resources carefully?

Q & A

Q1(CBSE 2011): What is coliform bacteria? What does its presence in water indicate?

Answer: Coliform is a group of bacteria which is found in human intestines. Its presence in water indicates contamination by disease-causing microbes. Its high presence in rivers and ponds elevates the risks of water borne diseases like gastroenteritis.

Q2(CBSE 2011): State two reasons of launching "Ganga Action Plan". Which bacteria was found in Ganga water indicating contamination?

Saturday 15 December 2012

CBSE Class 10 - Physics - CH11: The Human Eye and the Colourful World (NCERT Q & A)

The Human Eye and the Colourful World
 Dispersion of Light Which light bends the most? credits:wpclipart
(NCERT Chapter Q & A, Other Questions asked in CBSE Exam)

Q1(NCERT): What is meant by power of accommodation of the eye?

Answer: Power of accommodation is the ability of the eye lens to focus near and far objects clearly on the retina by adjusting its focal length. Power of accommodation of the eye is limited. It implies the focal length of the eye lens cannot be reduced beyond certain minimum limit.

Q2(CBSE 2011): A person cannot see the objects distinctly, when placed at a distance less than 50 cm.
(a) Identify the defect of vision.
(b) Give two reasons for this defect.
(c) Calculate the power and nature of the lens he should be using to see clearly the object placed at a distance of 25 cm from his eyes.
(d) Draw the ray diagrams for the defective and the corrected eye.

Answer: (a) Defect of vision = Hypermetropia  or Long-sightedness

Sunday 9 December 2012

CBSE Class 10 - Physics - CH11: The Human Eye and the Colourful World (Worksheet)

The Human Eye and the Colourful World
 Human Eye credits:openclipart
(Worksheet)

Fill in the blanks

1. The transparent spherical membrane covering the front of the eye is called ____________.

2. _______ is the surface which acts as screen and image is formed on it.

3. The coloured diaphragm between cornea and lens is known as __________.

4. A small hole in iris which controls the intensity of light entering the eye is called __________.