b. False
The statement ‘Big bang theorists believe that the universe is expanding and will eventually contract’ is false. The answer is letter B. The big bang theory suggests that the origin of the universe began with that exploded and expanded. It also states that the universe began in a single form of high condensed reactive matter and exploded forming the galaxies, planets, stars and other celestial bodies.
Answer:
FALSE
Explanation:
b) By what factor does the current change if the side dimensions of the membrane portion is halved? The other values do no change
increase by factor of 2
decrease by factor of 8
decrease by factor of 2
decrease by a factor of 4
increase by factor of 4
Answer:
Part a: The current is 1.49x10⁻¹² A
Part b: The current is decreased by a factor of 4.
Explanation:
Part a
The area is given as
A =(1.4*10⁻⁶)² =1.96*10⁻¹² m²
The resistance is given as where resistivity of the membrane material is 1.30 x 10⁷ ohms*m
R=pL/A =(1.3*10⁷)(7.5*10⁻⁹)/(1.96*10⁻¹²)
R=4.97x10¹⁰ ohms
So the resistance is 4.97x10¹⁰ ohms.
I=V/R =86.0x10⁻³/5.77x10¹⁰
I=1.49x10^⁻¹² A
So the current is 1.49x10⁻¹² A
b)
S=So/2=1.4/2 =0.7μm
A=(0.7*10^-6)^2=4.9*10⁻¹³ m²
R=pL/A =(1.3*10⁷)(7.5*10⁻⁹)/(4.9*10⁻¹³)
R=1.98x10¹¹ ohms
So the resistance is 1.98x10¹¹ ohms.
I=V/R =86.0x10⁻³/1.98x10¹¹
I2=4.52x10^⁻¹³ A
So the ratio of the new current vs the old current is as
I2/I=4.52x10^⁻¹³/1.49x10⁻¹²=0.25
So the current is decreased by a factor of 4.
The correct answer to the question will be that the electric force between them will be decreased.
EXPLANATION:
Let us consider the charge contained by A and B are denoted as Q and Q' respectively.
Let R is the separation distance between them.
As per Coulomb's law in electrostatics, the force of attraction or repulsion between the two charge bodies A and B will be -
Coulombic force F =
Here, is the permittivity of the medium in which the charges are present.
From above, we see that electric force is inversely proportional to the square of separation distance between them.
Mathematically it can be written:
As per the question, the distance between A and B is increased.
Hence, the electric force between A and B will be decreased.
transmission electron microscope
b.
scanning electron microscope
c.
compound light microscope
d.
dissecting microscope
Answer;
-Compound light microscope
Explanation;
-A compound microscope is a microscope that uses multiple lenses to enlarge the image of a sample. It is commonly used for viewing samples at high magnification (40 - 1000x), which is achieved by the combined effect of two sets of lenses: the ocular lens and the objective lenses.
-Compound microscopes usually include exchangeable objective lenses with different magnifications (e.g 4x, 10x, 40x and 60x), mounted on a turret, to adjust the magnification. These microscopes also include a condenser lens and iris diaphragm, which are important for regulating how light hits the sample.