Answer:
c. expanded polyurethane
Explanation:
Thermal performance of a building fabric is measured in terms of heat loss and is expressed as U-value or R-value. U-value is the rate of heat transferred through a structure divided by the difference in temperature across the structure with a unit of measurement of W/m²K.You can calculate the U-value of a by getting the reciprocal of the sum of thermal resistances , R, making the building material.
If you have the value of R, then U=1/R
Material size R U
plywood 1" 1.25 0.8
Poured concrete 2" 0.99 1.010
Expanded polyurethane 1" 6.5 0.1538
Asbestos shingles 1" 0.03 33.33
The material with lowest U-value is expanded polyurethane
Answer:
B = 7.6 T direction of + x
Explanation:
For the proton beam to continue in the same direction the electric and magnetic forces must be equal
= 0
= F_{e}
Fm = q E
The electric force is in the direction of the electric field because it is the charge of the positive proton, the electric force goes in the direction of –y, therefore, the magnetic force cancels this force must go in the direction of + y
The magnetic force is
F_{m} = q v x B = q v B sin θ
θ = 90
B = q E / q v
B = E / v
B = 800/105
B = 7.6 T
To find the direction of the magnetic field we use the right hand rule, the thumb goes in the direction of the proton velocity, the fingers extended in the direction of the magnetic field and the palm is the direction of force, for a positive charge.
Thumb goes in the direction of the + z axis
Palm in the direction of +y
Fingers point in the direction of + x
Answer:
B'=1.935 T
Explanation:
Given that
magnetic field ,B= 0.645 T
We know that magnetic filed in the solenoid is given as
I=Current
n=Number of turn per unit length
μ0 =magnetic permeability
Now when the current increased by 3 factors
I'=3 I
Then the magnetic filed
B'=3 B
That is why
B' = 3 x 0.645 T
B'=1.935 T
Therefore the new magnetic filed will be 1.935 T.
Answer:
1. D. They can be a substance, material, object or source of energy.
2. B. The properties will be different.
3. C. When two reactants form one product, the reaction is spontaneous.
In Longitudinal waves, particles of the medium vibrate around their mean positions. Their amplitude of vibration is in the direction of the propagation of the wave. In transverse wave of longitudinal wave, <em>the wavelength is always the distance between two particles which are in the same phase.</em>
If we take pressure waves, (sound waves), we have pressure variations created by sound wave along its path. Pressure is maximum at compression regions and pressure is minimum at rarefaction region. In between the two, pressure of air remains as the pressure when there is no wave.
<em>The wave length is then the distance between two consecutive rarefactions or two consecutive compression regions.</em>
<em>It is also the distance traveled by the wave in one time period.</em> Time period is the time the particles in the medium take to vibrate towards the end, turn back to reach the other end of their oscillation and then reach back their position.
