Focal length formula for mirror is 1/F=1/V+1/u, where V is the distance from pole to image and u is the distance from pole to object. Here we use sign conventions. Focal length is positive for a concave mirror and negative for convex mirror.

Given quadratic equation is, px² -2√5 px + 15 = 0

Compare px² -2√5 px + 15 = 0 with ax² + bx + c = 0

a = p , b = -2√5p , c = 15

We know that , If the roots of the quadratic equation are equal , then it's discriminant (D) equals to zero.
discriminant = 0
b² - 4ac = 0
( -2√5 p )² - 4× p × 15 = 0
20p² - 60p = 0
20p ( p - 3 ) = 0
p - 3 = 0
p = 3

Both the Bar and the Column charts display data using rectangular bars where the length of the bar is proportional to the data value. Both are used to compare two or more values. However, their difference lies in their orientation. A Bar chart is oriented horizontally whereas the Column chart is oriented vertically.

Bishamber was a middle age man. He was nearly as old as Bholi's father. He limped while walking. He had grown up children from his first wife.

 The impact of globalisation on Indian agriculture has been felt since colonial times. Raw cotton and spices were important export items from India. In 1917, Indian farmers revolted in Champaran against being forced to grow indigo in place of foodgrains, in order to supply dye to Britain’s flourishing textile industry. Thus, globalisation has had its boons and banes for Indian agriculture.

Post liberalisation, Indian farmers face new challenges in the form of competition from highly subsidised agriculture of developed nations. This prompts the need for making Indian agriculture successful and profitable by improving the conditions of small and marginal farmers, countering the negative effects of Green Revolution, developing and promoting organic farming, and diversifying cropping pattern from cereals to high-value crops.

Three human factors for the location of an industry →

 (a) Cheap labour must be available.

 (b) There should be easy flow and good flow of capital.

(c) Basic services like banking, insurance, transportation etc must be available.

A N S W E R
Three human factors which affect the industrial location are availability of cheap labour, availability of services such as consultants and financial advice and availability of market.

Three human factors which affect the industrial location are availability of cheap labour, availability of services such as consultants and financial advice and availability of market.

The series is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

The multiples of 4 in the above series is 4, 8, 12 = 3 terms

The probability of selecting a multiple of 4 = 

or = 0.2

From Number1,2,3,4,5,6,7,8,9,10,11,12,13,14,15

From 1 to 15, Multiples of 4 are 4, 8, 12 only

So Probability= Count of No. which are multiple of 4​/Total Number given

Prob.=3/15 ​= 1/5

The OSI Model (Open Systems Interconnection Model) is a conceptual framework used to describe the functions of a networking system. The OSI model characterizes computing functions into a universal set of rules and requirements in order to support interoperability between different products and software. In the OSI reference model, the communications between a computing system are split into seven different abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

ANSWER: Over irrigation is responsible for land degradation in punjab
Over irrigation is main cause of land degradation in Punjab due to waterlogging leading to increase in salinity and alkalinity in the soil. Punjab, Haryana, Uttar Pradesh are the states facing issue of land degradation.

उत्तर: पंजाब में भूमि क्षरण के लिए अधिक सिंचाई जिम्मेदार है
पंजाब में मिट्टी में लवणता और क्षारीयता में वृद्धि के कारण जलभराव का मुख्य कारण भूमि का क्षरण है। पंजाब, हरियाणा, उत्तर प्रदेश ऐसे राज्य हैं जो भूमि क्षरण के मुद्दे का सामना कर रहे हैं।

Which one of the following materials cannot be used to make a lens? Option A: Water Option B: Glass Option C: Plastic Option D: Clay

Answer: D

For lens preparation, transparent material may be used. Glass and water are transparent materials. There is a certain amount of plastic that is transparent so that the plastic can be used to make a lens, but the clay is an opaque substance so that the light can not be transmitted into it and the clay can not be used to create the lens.

माप, साइज या चौड़ाई

किसी वर्ग अंतराल का ऊपर का मान उस वर्ग अंतराल की उपरि वर्ग सीमा कहलाता है तथा उसका नीचे का मान उसकी निम्न वर्ग सीमा कहलाता है। किसी वर्ग की उपरि वर्ग सीमा और निम्न वर्ग सीमा का अंतर उस वर्ग की माप, साइज या चौड़ाई कहलाता है।

The ability of metals to be drawn into thin wire is called ductility. It is one such property of metals that is used to make wires from metals. Metals such as copper have high ductility and thus can be drawn into long and thin wires without breaking.

• Don't post personal information, mobile numbers and other details.
• Don't use this platform for chatting, social networking and making friends. This platform is meant only for asking subject specific and study related questions.
• Be nice and polite and avoid rude and abusive language. Avoid inappropriate language and attention, vulgar terms and anything sexually suggestive. Avoid harassment and bullying.
• Ask specific question which are clear and concise.

UV light (ultraviolet light) is having a wavelength between 10 and 400 nm that is shorter than the visible light but longer than the X-rays and is a type of electromagnetic radiation. These are present in sunlight and contributes 10% of the total light from the sun.

Ozone layer depletion is the thinning of the ozone layer present in the upper atmosphere

Causes of ozone depletion:

• Methyl bromide
• Nitrogen oxides released from freezers, air conditioners, aerosol products and industrial solvents
• Compounds such as CFCs break down into chlorine atoms in the atmosphere. These chlorine atoms break down O₃ into oxygen (O₂) and nascent oxygen (O).

Considering the loss of classroom teaching time due to the Covid-19 pandemic and lockdown, CBSE reduced the syllabus of classes 9 to 12 with the help of suggestions from NCERT.

The CBSE syllabus has been rationalized keeping intact the learning outcomes so that the core concepts of students can be retained.

Deleted syllabus of CBSE Class 10 Science

Given :

To Find : solve using substitution method

Solution :

  -----1

 ------2

Substitute the value of x from 1 in 2

So, x = 2 and y = 3

2. Ionic bonds are formed because of transfer of electrons from metal to non-metal. In this course, metals get positive charge because of transfer of electrons and non-metal gets negative charge because of acceptance of electrons. In other words bond formed between positive and negative ion is called ionic bond

1. 

The chemical bond formed by the sharing of an electron pair between two atoms so that both the atoms get their octet complete is called covalent bond.

The molecules formed as a result of sharing of electron between two atoms are called as covalent molecules.

The consumer movement in India has led to the formation of various organisations locally known as consumer forums or consumer protection councils. They guide consumers on how to file cases in the consumer court. On many occasions, they also represent individual consumers in the consumer courts. These voluntary organisations also receive financial support from the government for creating awareness among the people.

If you are living in a residential colony, you might have noticed name boards of Resident Welfare Associations. If there is any unfair trade practice meted out to their members they take up the case on their behalf.

The factors that gave birth to the consumer movement in India are manifold. It started as a "social force" with the need to protect and promote consumer interests against unfair and unethical trade practices. Extreme food shortages, hoarding, black marketing and adulteration of food led to the consumer movement becoming an organised arena in the 1960s. Till the 1970s, consumer organisations were mostly busy writing articles and holding exhibitions. More recently, there has been an upsurge in the number of consumer groups who have shown concern towards ration shop malpractices and overcrowding of public transport vehicles. In 1986, the Indian government enacted the Consumer Protection Act, also known as COPRA. This was a major step in the consumer movement in India.

 (ii) and (iii)​

propene, propyne

Unsaturated compounds have double or triple bonds between the carbon atoms.

Among the given options, propene and propyne have double and triple bonds respectively. Hence, these are unsaturated compounds.