28. Which of the following statements is correct? A. Mining sites are abandoned after excavation leaving deep scars. B. In states like Jharkhand, Chhattisgarh, Madhya Pradesh and Odisha deforestation due to mining has caused severe land degradation. C. In states of Punjab, Haryana, western Uttar Pradesh, over-irrigation is responsible for land degradation D. All of the above.
Answers
Answer:
D
Explanation:
All of the above because all the cause are the main reason for that
Answer:
gains gravitational potential energy which is proportional to the work done to raise the object against gravitational pull.
Similarly, an object gains some electric potential energy as it is moved against the electric field.
This energy is proportional to the amount of work done in moving the object from one point to another against the electric field. The electric potential is taken as zero at infinity.
POTENTIAL DIFFERENCE
The potential difference between two points in an electric circuit is defined as the amount of work in moving a unit charge from one point to the other point.
It is expressed as:
Potential difference = Work doneQuantity of charge moved
Potential difference, V = WQ
UNIT OF POTENTIAL DIFFERENCE
The SI unit of potential difference is volt.
The Potential difference between two points is said to be 1 volt if 1 joule of work is done in moving 1 coulomb of electric charge from one point to the other.
1V = 1 J C–1
Voltmeter: The potential difference is measured by means of an instrument called voltmeter whose terminals are connected across the points or parallel to the element whose potential is to be measured.rho, ρ, is quantitatively equal to the resistance R of a specimen such as a wire, multiplied by its cross-sectional area A, and divided by its length l; ρ = RA/l. The unit of resistance is the ohm. In the metre-kilogram-second (mks) system, the ratio of area in square metres to length in metres simplifies to just metres. Thus, in the metre-kilogram-second system, the unit of resistivity is ohm-metre. If lengths are measured in centimetres, resistivity may be expressed in units of ohm-centimetre.


Electric potential and potential difference
Tutormate > CBSE Syllabus-Class 10th Physics > Electric potential and potential difference
03 Electricity

ELECTRIC POTENTIAL
The electric potential (or potential) at a point in an electric field is defined as the work done in moving a unit positive charge from infinity to that point, without any acceleration.
Electric Potential is similar to flow of water from one end of a tube connected to a tank at a higher level to another tank at the other end of the tube at a lower level.
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