In the circuit shown below, 0.25 A of current flows through a 20-Ω resistor. How much voltage is needed to produce this current?

Why is Carbon Tetrahydride a covalent bond? plzzz helpppp!!!!!!

arlik [135]

Answer:

carbon has four unpaired electrons in its valence shell . hydrogen having one unpaired electron in its valence shell comes to bond with carbon by sharing a pair of electrons .since carbon needs 4 electrons to be stable, 4 hydrogen atoms take part in the bond . It's a covalent bond because the difference between the electronegativity of carbon and hydrogen is quite small .

7 0

2 years ago

A flatbed truck is carrying an 800-kg load of timber that is not tied down. The maximum friction force between the truck bed and

ycow [4]

Answer:

Acceleration a ≤ 3 m/s^2

the greatest acceleration that the truck can have without losing its load is 3 m/s^2

Explanation:

For the truck to accelerate without losing its load.

Acceleration force of truck must be less than or equal to the maximum friction force between the truck bed and the load.

Fa ≤ F(friction)

But;

Fa = mass × acceleration

Fa = ma

ma ≤ F(friction)

a ≤ (F(friction))/m ......1

Given;

Fa = mass × acceleration

Fa = ma

mass m = 800 kg

F(friction) = 2400 N

Substituting the given values into equation 1;

a ≤ F(friction)/m

a ≤ 2400N/800kg

a ≤ 3 m/s^2

the greatest acceleration that the truck can have without losing its load is 3 m/s^2

4 0

3 years ago

Check all that apply. The magnetic force on the current-carrying wire is strongest when the current is parallel to the magnetic

dedylja [7]

Answer:

The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field.

The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current.

The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.

Explanation:

The magnitude of the magnetic force exerted on a current-carrying wire due to a magnetic field is given by

$F=ILB sin \theta$ (1)

where I is the current, L the length of the wire, B the strength of the magnetic field, $\theta$ the angle between the direction of the field and the direction of the current.

Also, B, I and F in the formula are all perpendicular to each other. (2)

According to eq.(1), we see that the statement:

"The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines."

is correct, because when the current is perpendicular to the magnetic field, $\theta=90^{\circ}, sin \theta = 1$ and the force is maximum.

Moreover, according to (2), we also see that the statements

"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field. "

"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current. "

because F (the force) is perpendicular to both the magnetic field and the current.

5 0

2 years ago

Sue and Jenny kick a soccer ball at exactly the same time. Sue’s foot exerts a force of 52.6 N to the north. Jenny’s foot exerts

Karolina [17]

Using the addition of forces using right angled triangles. The resultant force sqaured. = 112.8 sqaured + 52.6 squared. So resultant force sqaured is 15490.6. So the resultant force is the sqaure root of this which is 124N to 3 significant figures

6 0

2 years ago

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A camera lens focuses on an object 75.0 cm from the lens. The image forms 3.50 cm behind the lens. What is the magnification of

Yakvenalex [24]

Answer:

Explanation:

Refraction by a Convex Lens

Refraction bends the light downward upon entering the glass because the bottom part of the ray hits the slow medium first.

Light travels more slowly in glass than in air. The amount of bending depends upon the index of refraction of the glass.

Image formation depends upon bending light rays with lenses.

Refraction bends the light downward again upon leaving the glass because the top part of the ray hits the faster medium first.

Index

Lens concepts

HyperPhysics***** Light and Vision R Nave

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Magnification:Transverse &Angular

The linear magnification or transverse magnification is the ratio of the image size to the object size. If the image and object are in the same medium it is just the image distance divided by the object distance.

Using the Gaussian form of the lens equation, a negative sign is used on the linear magnification equation as a reminder that all real images are inverted. If the image is virtual, the image distance will be negative, and the magnification will therefore be positive for the erect image.

If the media are different on the two sides of the surface or lens, the magnification is not quite so straigtforward. It can be variously expressed as

In this equation V is the vergence, n is the index of refraction, and u is used for the angle. Note that in this expression for the magnification, the minus sign doesn't appear. In this type of setting, the Cartesian sign convention is typically used and the object distance has a negative value. That takes care of the minus sign that is put in above in the Gaussian form.

The angular magnification of an instrument is the ratio of the angle subtended at the eye when using the instrument divided by the angular size without the instrument. An important example is the simple magnifier. The angular magnification of any optical system can be obtained from the system matrix for the system.

5 0

2 years ago