Answer:
The focal length of the lens must be 27.3cm
Explanation:
Image distance= -75 cm
Object distance= 20.0cm
From:
1/v + 1/u = 1/f
-1/75+ 1/20 = 1/f
11/300= 1/f
f= 300/11
f= 27.3cm
The focal length of the lens must be 27.3cm
Answer:
the loss of energy due to the Joule effect is the cause of the non-ohmic characteristic of the bulb
Explanation:
A resistance is formed of some type of metal, in a light bulb it is Tungsten, which for low current is a resistance that complies with the ohm law.
When the value of the current is increased the shock of the electors creates a Joule effect, which heats the metal, these shocks are due to atomic imperfections of the structure, this heating creates a loss of energy of the system that causes the characteristic to be lost linear between the voltage and the current, since the total energy balance must be preserved.
An approximate measure of the energy that is emitted is given by Stefan's law.
In short, the loss of energy due to the Joule effect is the cause of the non-ohmic characteristic of the bulb
Answer:
A. The particles will begin to move enough
that they slide past each other.
Explanation:
When the plastic cup is heated, the Kinetic energy of its particles starts increasing. As the temperature rises, the kinetic energy keeps increasing. With the increase of K.E, the particles start moving faster and faster. When the temperature finally reaches the melting point, the K.E of the molecules is enough to break the bonds and slide past each other.
Whichever person or group can build something to protect the egg from cracking when it is dropped from a high spot without it breaking or cracking wins
Answer:
v = √ 2 G M/ 
Explanation:
To find the escape velocity we can use the concept of mechanical energy, where the initial point is the surface of the earth and the end point is at the maximum distance from the projectile to the Earth.
Initial
Em₀ = K + U₀
Final
= 
The kinetic energy is k = ½ m v²
The gravitational potential energy is U = - G m M / r
r is the distance measured from the center of the Earth
How energy is conserved
Em₀ =
½ mv² - GmM / = -GmM / r
v² = 2 G M (1 / – 1 / r)
v = √ 2GM (1 / – 1 / r)
The escape velocity is that necessary to take the rocket to an infinite distance (r = ∞), whereby 1 /∞ = 0
v = √ 2GM /
