Answer:
Option (a), (b) and (c)
Explanation:
The resistance of a conductor depends on the length of the conductor, area of crossection of the conductor and the nature of the conductor.
The formula for the resistance is given by
R = ρ x l / A
Where, ρ is the resistivity of the conductor, l be the length of the conductor and A be the area of crossection of the conductor.
So, It depends on the length, area and the type of material.
The field lines spread apart as we move away from the charge, and they point away from the charge
Explanation:
The electric field produced by a single-point positive charge is a radial field, whose strength is given by the equation

where
k is the Coulomb's constant
Q is the magnitude of the charge
r is the distance from the charge at which the field is calculated
There are two pieces of information given by the field lines shown in the graph:
- The spacing between the lines gives an indication of the strength of the field: the closer to each other they are, the stronger the field. In this case, as we move away from the charge, the spacing between the lines increases, and this means that the field becomes weaker (in fact, it follows an inverse square law,

- The direction of the lines gives the direction of the electric field, which points away from the central charge. This is because the direction of the electric field corresponds to the direction of the force that a positive test charge would feel when immersed in the electric field: in this case, if we place a positive test charge in this field, then it would get repelled away from the central charge (remember that the electric force between two positive charges is repulsive), and therefore, the direction of the electric field is away from the central charge.
Learn more about electric field:
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Force of gravity on an object is the weight of the object and is given by mass times accerelation due to gravity. The accerelation due to gravity is the accerelation of an object in free fall and is given by 9.8m/s^2. Given that the force of gravity acting on a child's mass on earth is 490 newtns, i.e. F = mg which means that 490 newtons = 9.8 times mass. Therefore, mass of the child is 490 / 9.8 = 50 kg.
Answer:
Astronomers
Explanation:
Astronomy
Field of study
DescriptionAstronomy is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry to try and explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets.
https://en.wikipedia.org/wiki/Astronomer