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3 years ago

Why would it be incorrect to say that the bulb supplies 60 J of light energy energy each second

Physics

1 answer:

LekaFEV [45]3 years ago

4 0

Answer:

Explanation:

A 60W bulb , consumes electrical energy of 60 J per second but it does not give out all the energy in the form of light . Most of the energy consumed by it is wasted in the form of heat . Only a fraction of energy is converted into light energy .

Hence, it is wrong to say that bulb supplies 60 J of light energy each second .

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Naya [18.7K]

12 divided by 2/5 is 30.

The difference between 764.7 and 45.39 is 719.31.

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3 years ago

Read 2 more answers

What usually causes high concentration of minerals to form

grandymaker [24]

Answer:during the evaporation of liquids salt, sugar, reference to evaporates the cooling of liquids saturated solution at high temperatures and pressures new crystals may grow in solid materials diamonds from coal, metamorphism

Explanation:

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3 years ago

A merter stick pivoted at its center has a 150gm mass suspended at its 20cm mark. a) Where should an 100gm mass be placed to pro

IgorLugansk [536]

Answer:1) 100 gm mass should be placed at 95 cm mark.

2) Mass of 112.5 gm should be placed at 90 cm mark.

Explanation:

For equilibrium of the meter stick the sum of the moment's generated by the masses should be equal and opposite

Answer to part b)

Since a meter stick is 100 cm long and it is pivoted at it's center i.e at 50 cm

Thus

1) Moment generated by 100 gm mass about center = $M_{1}=m_{1}g\times r_{1}\\\\M_{1}=0.15\times 9.81\times 0.3=0.44145Nm$

Let a mass 'm' be placed at 90 cm mark thus moment it generates equals

$M_{2}=m\times 9.81\times 0.4=3.924m$

Equating both the moments we get

$0.44145=3.924m\\\\\therefore m=\frac{0.44145}{3.924}\times 1000grams\\\\\therefore m= 112.5grams$

Answer to part a)

Let the 100 grams weight be placed at a distance 'x' right of center

Moment generated by 100 grams weight equals

$M_{1}=0.1\times 9.81\times x$

equating the moments of the forces we get

$0.1\times 9.81\times x=0.15\times 0.3\times 9.81$

$\therefore x=\frac{0.4415}{.981}=45centimeters$

thus the mass of 100 gm should be placed at 95 cm mark in the scale.

8 0

4 years ago

Two positive charges are fixed a distance apart.the sun of their charges is Qt.what charge must each have in order to maximise t

romanna [79]

Answer:

Both charges must have the same charge, Qt/2.

Explanation:

Let the two charges have charge Q1 and Q2, respectively.

Use Coulombs's Law to find an expression for the force between the two charges.

$F = k_e\frac{Q_1Q_2}{r^2}$ , where

Ke is Coulomb's contant and

r is the distance between the charges.

We know from the question that

Q1 + Q2 = Qt

So,

Q2 = Qt - Q1

$F = k_e\frac{Q_1(Q_t - Q_1)}{r^2}$

Simplify to obtain,

$F = \frac{k_e}{r^2} (Q_tQ_1 - Q_1^2)$

In order to find the value of Q1 for which F is the maximum, we will use the optimization technique of calculus.

Differentiate F with respect to Q1,

$\frac{dF}{dQ_1} = \frac{k_e}{r^2} (Q_t - 2Q_1)$

Equate the differential to 0, to obtain the value of Q1 for which F is the maximum.

$\frac{k_e}{r^2} (Q_t - 2Q_1) = 0\\Q_t - 2Q_1 = 0\\2Q_1 = Q_t\\Q1 = \frac{Q_t}{2}$

It follows that

$Q_2 = \frac{Q_t}{2}$ .

6 0

3 years ago

The forces acting on a child sitting in a seat are described by the free-body diagram shown. What is the net force acting on the

r-ruslan [8.4K]

The net force is 0 N.

To find the total net force, all you need to do is add the forces.

So 100 + -100 = 0

Most of these questions are trick questions, but if you know Newton's laws of forces, then you should know that all forces should cancel out with each other.

Hope this helps!!!

3 0

3 years ago