A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses. High-power resistors that can dissipate many watts of electrical power as heat, may be used as part of motor controls, in power distribution systems, or as test loads for generators. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical
Answer:
I₂ = 0.04 W / m²
Explanation:
Sound intensity is the power emitted between the unit area
I = W / A
W = I A
sound is a wave that travels in space whereby its energy is distributed on the surface of a sphere
A = 4π r²
we substitute
W = I (4π r²)
the emission power is constant, so the intensity at two different points is
W = I₁ 4π r₁² = I₂ 4π r₂²
so the equation is
I₁ r₁² = I₂ r₂²
In this case the units are not shown in the exercise, suppose that all units are in the SI system
I₂ = 
let's calculate
I₂ = 4 
I₂ = 0.04 W / m²
Ticker Tape analysis is a common way of analyzing the motion of the objects to perform in the physics laboratory. A long tape is attached to a moving object and threaded through a device that places a tick upon the tape at regular intervals of time. This ticker tape can also determine if the object is fast or slow. It can also reveal if the object is moving with a constant velocity or accelerating. The changing velocity and acceleration represented by the changing distance between dots in the ticker tape. And also the constant velocity and therefore no acceleration represent the constant distance between dots.
Answer:
D. The ice-to-liquid phase change of water requires less energy than the liquid-to-vapor phase.
Explanation:
In the phase change from liquid to gas, the bonds between atoms are completely broken. The phase change from liquid to gas requires more energy because the bonds must be completely broken for it to take place, rather than just loosened as in the phase change of solid to liquid.
Phase changes can have a strong stabilizing effect on temperatures that are not near the melting and boiling points, since evaporation and condensation occur even at temperatures below the boiling point.
More energy is required to evaporate water below the boiling point than at the boiling point, because the kinetic energy of water molecules at temperatures below 100°C is less than that at 100°C, so less energy is available from random thermal motions.
Explanation:
In a chemical reaction, when mass is conserved , the number of atoms or moles of the reactants must be equal to the number of moles or atoms in the products side.
From the diagram, we should carefully look to see if the number of atoms that makes up the reactants are equal to those on the product side.
For example:
A + B → AB
Here, mass is conserved because, on the reactant side, we have 1 atom of A and on the product side we have 1 atom of A
For B, on the reactant side, we have 1 atom of B and on the product side, we have 1 atom of B.
