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2 years ago

Why are not all microorganism harmful?

1 answer:

8 0

In nature there are two categories of microorganisms as relating to health. Microorganisms that are considered harmful to humans are called pathogens and these cause disease. Examples include bacteria such as streptococcus which cause sore throat and salmonella which cause typhoid disease.

There are some microorganisms which are helpful to man and they live mostly on the skin of man or in his gut and are mostly bacteria. They are collectively called bacterial normal flora.

In man the normal bacterial flora of the skin include staphylococcus found on dry skin, cornybacteria found in moist skin sites and propionibacteria in the sebaceous sites (head, neck, trunk) of the body. Normal bacterial flora of the gut include Escherichia coli.

One of the major function of bacterial flora is actually to protect our bodies by competing for space with pathogens preventing them from gaining a foothold in our bodies.

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A circular coil of radius 5.0 cm and resistance 0.20 Ω is placed in a uniform magnetic field perpendicular to the plane of the c

Romashka [77]

Answer:

Explanation:

Given that,

Assume number of turn is

N= 1

Radius of coil is.

r = 5cm = 0.05m

Then, Area of the surface is given as

A = πr² = π × 0.05²

A = 7.85 × 10^-3 m²

Resistance of

R = 0.20 Ω

The magnetic field is a function of time

B = 0.50exp(-20t) T

Magnitude of induce current at

t = 2s

We need to find the induced emf

This induced voltage, ε can be quantified by:

ε = −NdΦ/dt

Φ = BAcosθ, but θ = 90°, they are perpendicular

So, Φ = BA

ε = −NdΦ/dt = −N d(BA) / dt

A is a constant

ε = −NA dB/dt

Then, B = 0.50exp(-20t)

So, dB/dt = 0.5 × -20 exp(-20t)

dB/dt = -10exp(-20t)

So,

ε = −NA dB/dt

ε = −NA × -10exp(-20t)

ε = 10 × NA exp(-20t)

Now from ohms law, ε = iR

So, I = ε / R

I = 10 × NA exp(-20t) / R

Substituting the values given

I = 10×1× 7.85 ×10^-3×exp(-20×2)/0.2

I = 1.67 × 10^-18 A

6 0

3 years ago

Which of the following represents a fully plastic collision? 1. Two billiard balls hit each other then move in opposite directio

Nutka1998 [239]

Answer:

Option (4)

Explanation:

There are two types of collision.

Perfectly elastic collision: the collision in which the momentum and kinetic energy is conserved. There is no loss of energy in other forms of energy.

Perfectly plastic collision: The collision in which the momentum is conserved and kinetic energy is not conserved. The two bodies stick after the collision.

Here, the bullet hits the block and then embedded in the block, it is the example of plastic collision.

3 0

3 years ago

If an object 18 millimeters high is placed 12 millimeters from a diverging lens and the image is formed 4 millimeters in front o

Svetach [21]

C.
18 / x = 12 / 4
12x = 72
x = 6mm

6 0

2 years ago

Earth's gravity acts upon objects with a steady force of __________.

luda_lava [24]

None of the choices is a force. 'a' and 'b' are speeds. 'C' and 'd' are accelerations. ... The steady force of gravity is 9.8 newtons PER KILOGRAM of mass. ... The question is written by someonewho very much wants to discourage anyone interested in Physics.

6 0

3 years ago

Read 2 more answers

Which philosopher believed that the soul operated on three levels: reason, will, and desire?

garri49 [273]

Answer : Plato

Explanation : Plato believed that the soul operated on three levels

Reason, will and desire

According to Plato, the soul or mind is separable from the body, true knowledge is discovered through reflection and logic , sense impressions and observations are unreliable.

He also explains the Tripartite soul, the soul operates on three levels thought or reason , spirit or will and appetite or desire.

7 0

2 years ago

Read 2 more answers