Question

Trace the F1 generation formed by crossing two plants with separate traits for shape and seed colour round green (RRyy) and wrinkled yellow(rrYY). Mention the characteristic exhibited by it​

Answer 1

Explanation:

The "three principal rays" which are used for visualizing the image location and size are: A ray from the top of the object proceeding parallel to the centerline perpendicular to the lens. Beyond the lens, it will pass through the principal focal point. ... A ray through the center of the lens, which will be undeflected.

Answer 2

= F/A formula

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This concept is most applicable to gases, which are so easily compressed under pressure, so considerably increasing their density - this happens with the Earth's atmosphere.

Also, the greater the column of fluid e.g. water, the greater the pressure created - the greater weight acting on a given area.

See later section on pressure in liquids.

See also

Particle models of gases–liquids–solids, explaining properties, state changes (GCSE chemistry notes)

The density of materials and the particle model of matter (GCSE physics notes)

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(b) Pressure created by standing objects and in fluids, calculations, P = F/A formula

Pressure is defined as force per unit area and is calculated from the simple formula

pressure = force normal to the surface ÷ area of that surface,

P = F / A, F = P x A, A = F / P

P, pressure in pascals (Pa); F, contact force in newtons (N); A, area on which force acts in square metres (m2)

A force of 1 N acting on 1 m2 creates a pressure of 1 Pa

Pressures caused by standing objects - some simple calculations, if occasionally painful !

Any solid object standing on a solid surface will, due to the force gravity, create a pressure on the surface due to its weight.

This is a normal contact force, balanced by the compressed atoms of the solid surface pushing back up.

(This complies with Newton's 1st Law of Motion)

Ignoring the different weights of people (the weight 'force'), you should realise from the formula why it is better to be trodden on by a broad shoe sole than a stiletto heel !!!! (CLUE !!! P = F / A, no exam pressure here !!!)

In moving around the particles of a fluid collide with each other and with any surface they are in contact with.

Although the mass of an individual particle is minute and each collision involves the transfer of an equally minute amount of kinetic energy, collectively the trillions of collisions cause a pressure to be exerted in both gases and liquids.

The combined effects of these particle collisions produces a net resultant force at right angles to the surface of contact with an object or side of a container.

e.g. the pressure of gases in a container or the pressure from the atmosphere of air pressure around you.