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HALDWANI

CLASSES BY JOSHI SIR

CONT: 8410108680

CLASS 6

CLASS 8 AI

CLASS 10

Human Eye And Colorful world

(1 Mark Questions)

(Multiple Choice Question)

Ques1. 

When a person is myopic, he/ she can clearly see:

(a) both nearby and far off objects

(b) Only nearby objects

(c) only far off objects

(d) Neither nearby nor far off objects

Ques2. 

The defect of myopia can be corrected by using:

(a) Concave lens

(b) Convex lens

(c) Either concave or convex

(d) A complicated combination of lenses.

Ques3. 

Which of the following phenomenonc contributes significantly to the reddish

appearance of the sun at sunrise or sunset?

(a) Dispersion of light

(b) Scattering of light

(c) Total internal Reflection

(d) Reflection of light from the earth

Ques4. 

The focal length of the eye lens increases when eye muscles.

(a) are relaxed and lens becomes thinner

(b) contract and lens becomes thicker

(c) are relaxed and lens becomes thicker

(d) Contract and lens becomes thinner.

Ques5.

The human eye can focus objects at different distances by adjusting the focal length

of the eye lens. This is due to

(a) Presbyopia

(b) Accommodation

(c) Near-sightedness

(d) Far-sightedness

(Very Short Questions)

Ques6. 

Define power of accommodation?

Ques7. 

Which part of the human eye provides most of the refraction for the light rays

entering the eye?

Ques8. 

What happens to the pupil of the eye when the light is very bright?

Ques9. 

Name the muscle responsible for bringing change in the focal length of the eye lens?

Ques10. 

What is the nature of image formed on the retina of the eye?

(2Mark Questions)

Ques11. 

The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem.

Ques12.

Name the part of the eye that

(a) determines the colour of a person’s eye

(b) Controls the amount of light entering the eye

Ques13.

 State the role of eye lens in the human eye?

Ques14. 

A student has difficulty reading the blackboard while sitting in the last row. What

Could be the defect the child is suffering from? How can it be corrected?

Ques15.

 A person wears eye glass of focal length 70 cm what is the far point of the person?

(5 Mark Questions,  Attempt any 2)

Ques16.

A 14 year old student is not able to see clearly the questions written of the black

board placed at a distance of 5 m from him.

(a) Name the defect of vision he is suffering from?

(b) Draw the diagram to show this defect?

(c) Name the type of lens used to correct this defect?

(d) Name two possible cause of this defect.

(e) Draw the diagram to show how this defect can be corrected.

Ques17. 

(a) Explain the following terms used in relation to defects in vision and correction provided by them:
(i) Myopia (ii) Astigmatism (iii) Bifocal lenses (iv) Far-sightedness.

(b) Why is the normal eye unable to focus on an object placed within 10 cm from the eye?

Ques18.

Make a diagram to show how hypermetropia is corrected. The near point of a

hypermetropic eye is 1 m. What is the power of the lens required to correct this defect?

Assume that near point of the normal eye is 25 cm.

LIGHT (T.S. 1)

1 Marks Questions

Ques1. What is magnification of plane mirror?
Ques2. When a convex lens will act as magnifying Glass?
Ques3. The radius of curvature of a convex mirror is 20cm. What is its focal length?
Ques4. What is power of Lens of focal length of 20cm?
Ques5. Explain why a ray of light passing through the centre of curvature of a concave mirror, gets reflected along the same path.


2 Marks Questions

Ques6. Define the following terms in the context of spherical mirrors:
1) Pole
2) Center of curvature
3)Principal axis
4)Principal focus.

Ques7. The refractive indices of glass and water with respect to air are 3/2 and 4/3 respectively. If speed of light in glass is 2x108 m/s, find the speed of light in water.

Ques8. What is meant by power of a lens ? Write its S.I. unit.

Ques9. The linear magnification produced by a spherical mirror is +1/3. Analysing this value, state the type of mirror and  position of the object with respect to the pole of the mirror. Draw any diagram to justify your answer.

Ques10. A concave mirror produces three times magnified (enlarged) real image of an object 10 cm in front of it. Where is the image located?

3 Marks Questions(Attempt any 5)

Ques11. Draw a ray diagram to show the path of the reflected ray in each of the following cases.

A ray of light incident on a convex mirror:  

1...strikes at its pole making an angle θ theta from the principal axis.

2....is directed towards its principal focus.

3... is parallel to its principal axis.

Ques12. If the image formed by a mirror for all positions of the object placed in front of it is always virtual and diminished, state the type of the mirror. Draw any ray diagram in support of your answer.  

Ques13. An object is placed at a distance of 12 cm in front of a concave mirror. It forms a real image four times larger than the object. Calculate the distance of the image from the mirror

Ques14. A convex mirror used on a bus has a focal length of 200 cm. If a scooter is located at 100 cm. from this mirror find the position, nature and magnification of the image formed in the mirror.

Ques15. A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed?

Ques16. State the mirror formula for determining the focal length of spherical mirrors write the meanings of the symbols used An object is placed at a distance of 25 cm. from a concave mirror of focal length 15 cm. Calculate the distance of the image from the mirror.

Ques17. An object is kept at a distance of

(i) a/2   (ii) (3a/2) from a convex lens having focal length of magnitude (a) Draw ray diagrams showing the formation of images formed in the two cases.

5 Marks Questions(Attempt Any 2)

Ques18. Name the type of mirrors used in the following situations: 
A) Headlights of a car
B) Rear-view mirror of vehicle
C) Solar furnace
Support your answer with reason

Ques19. A convex lens has a focal length of 10 cm. At what distance from the lens should the object be placed so that it forms a real and inverted image 20 cm. away from the lens? What would be the size of the image formed if the object is 2 cm high? With the help of a ray diagram show the formation of the image by the lens in this case?

Ques20. One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answers experimentally. Explain your observations.

start text, i Principal focus.

D. P. P. Electricity

D.P.P. 1                                                2-July-2020

◾️Q 1. What is meant by electric current? Name and define its SI unit. In a conductor electrons are flowing from B to A. What is the direction of conventional current? Give justification for your answer.
A steady current of 1 ampere flows through a conductor. Calculate the number of electrons that flows through any section of the conductor in 1 second. (Charge on electron 1.6 X 10-19 coulomb).

◽️ANSWER:- ELECTRIC CURRENT :Electric current is the amount of charge flowing through a conductor per unit time. OR , 

We can say that ELECTRIC CURRENT is the rate of flow of charge.

➡️Its SI unit is AMPERE.

WHAT IS 1 AMPERE -> The current flowing through conductor is said to be 1 Ampere if 1 coloumb of charge passes through it in 1 sec.

Current = Charge / Time

1 Ampere = 1 coloumb / 1 second

➡️ In a conductor, if electrons are flowing from B to A, then the direction of conventional current is from A to B.

➡️Justification -> Because, the direction of conventional current is considered opposite to the flow of electrons. Electric current comprises of the flow of positive charge. So, its direction will be opposite to the direction of negative charges that are electrons.

1 Ampere equals 1 Coulomb per second. Since each electron has a negative charge of e≈1.602⋅10−19     C     $e\approx 1.602\cdot {10}^{-19}C$, the number of electrons per second for 1C is 1Ce≈6.242*1018 $\frac{1C}{e}\approx \mathrm{6.242*}{10}^{18}$.

❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️

◾️Q2. Define 1 volt. Express it in terms of SI unit of work and charge calculate the amount of energy consumed in carrying a charge of 1 coulomb through a battery of 3 V.

◻️ANSWER  If 1 joule of work is done to carry 1 coulomb of charge from one point to another point , then it is said to be 1 V

Since we know that V=W/Q

so, put V = 3V And Q=1 c

by equating this in formula we get 3 j

❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️

◾️Q3. How is an ammeter connected in a circuit to measure current flowing through it?

◽️ANSWER: The ammeter is connected ‘in series’. This means that it is connected such that all the current must flow through it.

❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️❌️

◾️Q4. A piece of wire of resistance 20 Ω is drawn out so that its length is increased to twice its original length. Calculate the resistance of the wire in the new Situation.

◻️ANSWER: Given resistance = R1 = 20 ohm

Let length of the wire = L

Therefore, new length of the wire = 2L

Since, when the length is doubled, cross sectional area of the wire becomes half.

Therefore, new resistance = R = 2L/ (A/2) =4L/A

R = 4 x 20 (since, L/A = resistance)

R = 80 ohm.

Life process Important Questions

👉Answers to these questions👈
Q1. What are nutrients?

Q2. What is autotrophic nutrition?

Q3. What is heterotrophic nutrition?

Q4. What are the raw materials required for photosynthesis?

Q5. From where do the green plants get carbon dioxide? 

Q6. Why are minerals essential in photosynthesis?

Q7. What is holozoic nutrition?

Q8. What are saprotrophs?

Q9. Name the different types of heterotrophic nutrition?

Q10. What would be the consequences of deficiency of haemoglobin in blood.

SHORT ANSWER QUESTIONS

Q1. What is the importance of nutrients?

Q2. Give account of the reaction of the photosynthetic reaction?

Q3. Write short notes on absorption?

Q4. What is the function of large intestine in the human digestive system?

Q5. How is food digested in amoeba?

Transportation

22-May-2020

Two types of blood vessels are arteries and veins which are connected to the heart for transporting blood.

• Arteries –
• Carry blood rich in oxygen from the heart to all the cells of the body.
• The pressure exerted by the arteries while blood leave heart is rapid and thus wall walls of arteries are thick.
• The arteries divide in to extremely small thin branches on reaching the tissues. These small branches are called as capillaries.
  
• Capillaries have walls and are one-cell thick through which the exchange of materials between the blood and surrounding cells take place across this thin wall.
  

Veins

• Veins carry blood rich in carbon di oxide from all the cells of the body to the heart.
• The pressure exerted by the walls of the veins is less and have thin walls.
• Valves present in the veins ensure that the blood flows only towards the heart.

HUMAN CIRCULATORY SYSTEM

* The human circulatory system consists of a network of arteries, veins, and capillaries, with the heart pumping blood through it.

* Its primary role is to provide essential nutrients, minerals, and hormones to various parts of the body. * Alternatively, the circulatory system is also responsible for collecting metabolic waste and toxins from the cells and tissues to be purified or expelled from the body.

FEATURES OF CIRCULATORY SYSTEM

The crucial features of human circulatory are as follows:

• The human circulatory system consists of blood, heart, blood vessels, and lymph.
• The human circulatory system circulates blood through two loops (double circulation) – One for oxygenated blood, another for deoxygenated blood.
• The human heart consists of four chambers – two ventricles and two auricles.
• The human circulatory system possesses a body-wide network of blood vessels. These comprise of arteries, veins, and capillaries.
• The primary function of blood vessels is to transport oxygenated blood and nutrients to all parts of the body. It is also tasked with collecting metabolic wastes to be expelled from the body.
• Most circulatory system diagrams do not visually represent is its sheer length. Theoretically, if the veins, arteries, and capillaries of a human were laid out, end to end, it would span a total distance of 1,00,000 kilometres (or roughly eight times the diameter of the Earth).

23-May-2020

TRANSPORTATION IN PLANTS

1. Transportation is a vital process in plants.

This process involves the transportation of water and necessary nutrients to all parts of the plant for its survival.

2. Food and water transportation takes place separately in plants.

3. Xylem transports water and phloem transports food.

PHLOEM

1.  The phloem is responsible for translocation of nutrients and sugar like carbohydrates, produced by the leaves to areas of the plant that are metabolically active.

2. Sieve tubes, companion cells, phloem fibres, and phloem parenchyma cells are the components of this tissue.

3. The flow of material through phloem is bidirectional.

EXCRETION

Life Process QUESTIONS

EXCRETION

Excretion is a biological process by which an organism get rid of excess or toxic waste products of metabolism.

Excretion removes unwanted by-products of metabolism,toxic chemical substances, regulate the ionic concentration of body fluids,regulates water content of body,regulate pH of body fluids.

EXCRETION IN HUMANS

HUMAN EXCRETORY SYSTEM

It consists of a pair of Kidneys, a pair of ureters, Urinary bladder and Urethra.
The Kidneys are located in the abdominal cavity, situated below the level of last thoracic and third lumbar vertebra close to the dorsal inner wall of abdominal cavity.
Each kidney is been shaped reddish brown.
The right kidney is lower and smaller than left kidney because the liver takes up much space on the right side.
From each kidney, one ureter arises, and the two Ureters open obliquely into the Urinary bladder, which is a hollow, muscular sac-like structure that stores urine.
Urethra is the membranous tube that arises from the neck of the bladder and conduct the urine to the exterior.

Internally a kidney is made of numerous microscopic excretory units called nephrons.

The function of kidney is filtration of blood to excrete the waste products of metabolism. The kidney filters about 190 litres of blood to produce 0.9-21 of urine daily.

STRUCTURE OF NEPHRONS

Each nephron has cup shaped upper end called Bowman's Capsule.It contain bundles of blood capillaries called glomerulus. The Bowman's capsule and glomerulus together form globular body called renal corpuscle.

The blood in the capillaries of glomerulus come from aorta by renal arteries and after passing through glomerulus it returns to the posterior vena cava via renal vein.The blood entering into glomerulus carries waste material which are filtered out in the Bowman's capsule.

Filtration is possible because walls of glomerular capillaries and Bowman's capsule are very thin and selectively permeable.

PROCESS OF FILTRATION 

• A pair of kidneys, a pair of ureters, a urinary bladder and a urethra constitutes the human excretory system.
• Kidneys are present on either side of the backbone in the abdomen.
• Kidneys produce urine and urine from kidney passes through the ureters into the urinary bladder and remains stored their until it is released through the urethra.

Fig. Human excretory system  

• Urine is produced to filter out waste products from the blood.
• Nephrons are basic structural and functional unit of kidney.
• Cluster of thin walled blood capillaries called glomerulus in the nephron filtrate the urine and each cluster is associated with cup shaped end of a tube called Bowman’s capsule.

Fig. Nephron  

• Substances like glucose, amino acids, salts and a major amount of water is selectively reabsorbed from the initial filtrate as the urine flows along the tube.
• Reabsorption depends on the amount of excess water in the body and dissolved waste to be excreted.
• The urine from kidney enters the long tube called ureter.
• Ureter connects the kidney with the urinary bladder and urine from the kidney is passed to urinary bladder and stored in the bladder.
• When the pressure in the expanded bladder leads to the urge to urinate, the urine is passed out through urethra.

EXCRETION IN PLANTS

Excretion is the removal of waste from the body. Plants also produce waste products but very slowly and in very small amounts. They do not have any special organ for the removal of their waste product.

The waste products of a plant are carbon dioxide, water vapour and oxygen. While carbon dioxide and water vapour are waste products of respiration, oxygen is a waste product of photosynthesis. These waste products are removed through stomata in leaves and lenticels in stems and are released into the air.

Some of the waste products are stored in the leaves, bark and fruits of a plant or a tree. Trees get rid of them when dead leaves bark and ripe fruits fall off from them. Some plants store waste in their fruits in the form of solid bodies called raphides. For example, fruit yam has needle-shaped raphides on its surface. Plants also secrete waste in the form of gum and resins from their stem and branches.

Therefore, various methods used by plants to get rid of their waste products are:

• Gaseous waste through stomata and lenticels.
• Stored solid and liquid waste by shedding leaves, peeling of bark and falling of fruits.
• By secreting waste in the form of gum and resins.
• Excrete waste into the soil around them.