20. A semiconductor is a
crystalline solid that conducts current under any condition
metallic solid that conducts current under any condition
metallic solid that conducts current under certain conditions
crystalline solid that conducts current under certain conditions
Answer:
D. crystalline solid that conducts current under certain conditions
Explanation:
Semiconductors are crystalline solids that has the ability to conduct electrical currents but on certain conditions e.g heat. The conduction of semiconductors is less than that of conductors (metals) but more than insulators (nonmetals), hence, they are said to be intermediates of conductors and insulators in terms of electrical conductivity.
Examples of semiconductors are silicon, boron, carbon, germanium, arsenic etc.
A sound frequency 100Hz and wavelength 3.34m is travelling through air, calculate the Velocity of sound in air.
Answer:
334m/s
Explanation:
If you take the data you gave and insert it into the equation f=v/λ the frequency would come out to be 3.34m
334 m/s is the Velocity of sound in air.
What is the velocity of a wave?Wave velocity in common usage refers to speed, although, properly, velocity implies both speed and direction.
The velocity of a wave is equal to the product of its wavelength and frequency (number of vibrations per second) and is independent of its intensity.
Mathematically , v=fλ
According to the question,
Sound frequency (f) = 100Hz
Wavelength (λ)= 3.34m
Computing the values in the formula,
v=fλ
v = 100Hz x 3.34m
v= 334m/s
Therefore,
Velocity of sound in air is 334 m/s.
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absolute potential difference ,due of point charge of 1C at a distance of 1 m is given by
Answer:
[tex] \implies U = \dfrac{kq}{r} [/tex]
[tex]\implies U = \dfrac{9 \times {10}^{9} \times 1}{1} [/tex]
[tex]\implies U = 9 \times {10}^{9} \: J[/tex]
We have that absolute potential difference ,due of point charge of 1C at a distance of 1 m is given by
[tex]\rho=9x10 ^{10}J[/tex]
From the question we are told that
point charge of 1C at a distance of 1 m
Generally the equation for the Electrostatic potential energy is mathematically given as
[tex]\rho=\frac{kq_1q_2}{r}[/tex]
Where k is a constant
[tex]k=9*10^9Nm^2/c^2[/tex]
Therefore
[tex]\rho=\frac{(9*10^9)1*10^(-6)*1*10^{-6}}{1}[/tex]
[tex]\rho=9x10 ^{10}J[/tex]
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Which is an outer planet?
Answer:
pluto
Explanation:
Dwarf because it is very minut
Answer:
I think Saturn.
Explanation:
I think the inner planets are Mercury, Venus, Earth and Mars whereas the outer ones are Jupiter, Saturn, Uranus and Neptune.
A variable is a letter that stands in for a number and unit... True or False?
give one example where friction is a hindrance.
Answer:
an example of when friction is a hindrance, is if someone with shorts is sliding down a slide. their skin rubbing on the slide will cause friction and will slow them down. another example is if you're dragging a large wooden box across the floor. the wood and the floor interacting cause friction and will make it more difficult to push the box.
Explanation:
hope this helps :D
which is part of the convection cycle in earths atmosphere?
a. hot, denser air rises
b. cold, denser air rises
c. hot, less-dense air rises
d. cold, less-dense air falls
Why do scientists not use US customary units when reporting their data?
One of the scientist's jobs is to report the results of his experiments to all the other scientists in the world.
There isn't a single real science shop anywhere in the world that uses the US customary system of units. Not one.
Even in the measly three countries that use it for measuring carpet, pumping gas, and weighing fish ... Myanmar, Liberia, an the USA ... the scientists do their work in the SI/MKS/metric system.
an electron is moving at 3.6 x 10^3 m/s. a photon with what wavelength would have the same momentum????
Answer:
The wavelength of the photon that would have the same momentum as the electron is 202.2180996 nm
Explanation:
The velocity of the electron, v = 3.6 × 10³ m/s
The momentum of an electron, [tex]p_e[/tex] = m × v
Where;
v = The mass of the electron = 9.109 × 10⁻³¹ kg
∴ [tex]p_e[/tex] = 9.109 × 10⁻³¹ kg × 3.6 × 10³ m/s = 3.27924 × 10⁻²⁷ kg·m/s
According to the de Broglie equation, the momentum of a photon, p, is given as follows;
p = h/λ
Where;
h = 6.63 × 10⁻³⁴ J·s
λ = The wavelength of the photon
∴ λ = h/p
According to the question, we have;
p = [tex]p_e[/tex] = 3.27924 × 10⁻²⁷ kg·m/s
∴ λ = 6.63 × 10⁻³⁴ J·s/(3.27924 × 10⁻²⁷ kg·m/s) = 2.02180993 × 10⁻⁷ m
The wavelength of the photon, λ = 2.02180993 × 10⁻⁷ m = 202.2180993 × 10⁻⁹ m = 202.2180993 nm.
HELP ASAP
A. 1.09 A
B. 1.20 A
C.0.910 A
D. 0.830 A
Answer:
The answer should be: 1.20 A
Explanation:
A particular electric car is supplied with 300 kJ of chemical energy by the battery. Of this, a total of 70.5 kJ of energy is wasted as heat.
Calculate the overall efficiency of the electric car.
Supplied energy=300kJ
Wasted energy=70.5JUsed energy:-
[tex]\\ \sf\longmapsto 300-70.5=229.5kJ[/tex]
We know
[tex]\boxed{\sf Efficiency=\dfrac{Used\:Energy}{Supplied\:Energy}\times 100}[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{300}\times 100[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{3}[/tex]
[tex]\\ \sf\longmapsto Efficiency=76.5\%[/tex]
The overall efficiency of the electric car = 76.5 %
To find the efficiency the given values are:
Energy supplied = 300 kJ
Energy wasted = 70.5 kJ
Define efficiency and calculate the value of efficiency.In the system the output energy is compared to the input energy is known as efficiency. That can be written as percentage ratio of output energy to the input energy.
Formula of efficiency is,
Efficiency = ( E out / E in ) × 100
Here, Energy supplied = 300 kJ
so, energy used = Energy supplied - Energy wasted
= 300 - 70.5
= 229.5 kJ
Thus, substituting E out = 300 kJ , E in = 229.5 kJ
Efficiency = ( 229.5 / 300 ) ×100
= 229.5 / 3
= 76.5
Hence, The overall efficiency of the electric car is 76.5 %
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Why is it difficult to maintain constant speed of a vehicle?
Answer:
The road surface is always rough, so the frictional force between the tires and the road surface make it difficult to maintain constant speed because acceleration always changes.
For saving lives, what is the most important safety feature on a car? A. Air bag B. Safety Belt C. Anti-lock brakes
For saving lives the most important safety feature on a car is B. Safety Belt
What are safety features of a car ?Safety features of a car is a feature of a product designed to ensure or increase safety.
Air bag and Anti-lock brakes are the supplemental protection and designed to work best with combination with seat bells.
Air bag reduce the chance that upper body or head will strike the vehicle's interior during a crash alongside with belt that will also hold your upper body
so, the primary safety feature is seat belt and Air bag and Anti-lock brakes comes in secondary safety feature as they increases the safety and risk of getting an injury during any accident
correct answer is B. Safety Belt
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(d) Below shows a hydraulic press with a pump piston of area 4 cm2 and a ram area of
12 cm2 . IF A force of 300 N is applied on the pump piston, find:
(i)the maximum load on the ram.
(ii) the velocity ratio of the machine.
(iii) the mechanical advantage of the machine.
(iv)the efficiency of the machine.
Answer:
Explanation:
hi
how do u calculate the kinetic energy of a ball of mass 0.25kg being kicked vertically upwards with a speed of 5m/s
Answer:
3.125J
Explanation:
K.E.= 1/2(mass)(velocity)^2
K.E.=1/2(0.25)(5)^2=3.125
what do you mean by scattering of light
Answer:
Scattering of light is the phenomenon in which light rays get deviated from its straight path on striking an obstacle like dust or gas molecules, water vapours etc. Scattering of light gives rise to many spectacular phenomena such as Tyndall effect and the “red hues of sunrise and sunset”.
.
What is the equation for work?
Work = force / distance
Work = force - distance
Work = force + distance
Work = force * distance
Answer:
Work = F X D
Explanation:
Work (J) equals Force (N) multiplied by Distance (M)
help with this physics question please :)
Answer:
is that rm in you profile pic
can someone please help me with a and b? what do they mean by amplitude?
Explanation:
first answer is that the to and fro movement of a pendulum is known as amplitude
In----- theory, the actual wishes that are threatening to the dreamers conscious awareness are disguised
Answer:
Unconscious wish fulfillment
Explanation:
Unconscious wish fulfillment
(In the unconscious wish fulfillment theory, the actual wishes of the dreamer that are threatening to the dreamer's conscious awareness are disguised.)
if the pelican in item 3 was traveling at the same speed but was only 2.7m above the water, how far would the fish travel horizontally before hitting the water?
Answer:
5.66 m
Explanation:
From online sources, the speed in item 3 being referred to was discovered to be 7.62 m/s
Now, let's get the time of flight from one of Newton's equation of motion;
S = ut + ½gt²
Considering the vertical component, we have u = 0 m/s.
Thus;.
S = ½gt²
Plugging in the relevant values;
2.7 = ½ × 9.8 × t²
t² = 2.7/4.9
t = √(2.7/4.9)
t = 0.7423 s
Now, when we consider the horizontal component of the motion, we have;
S = vt
Where;
S is the distance the fish will travel horizontally before hitting the water.
v = 7.62 m/s
t = 0.7423
Thus
s = 7.62 × 0.7423
s ≈ 5.66 m
Which of the following is evidence for continental drift?
A car has a mass of 2000 kg. While it is traveling along a perfectly flat road, it goes around an unbanked turn that has a radius of 40.0 m. The coefficient of static friction between the car tires and the road is 0.500. The car travels successfully around the turn at a constant speed of 10.0 m/s. Calculate the magnitude of the car's acceleration as it goes around the turn. _______ m/s^2
Answer:
2.5 m/s²
Explanation:
The given parameters are;
The mass of the car, m = 2,000 kg
The radius of the car, r = 40.0 m
The coefficient of friction between the car tires and the road, μ = 0.500
The constant speed with which the car moves, v = 10.0 m/s
The normal reaction of the road on the car, N = The weight of the car;
∴ N = m × g
Where;
g = The acceleration due to gravity ≈ 9.81 m/s²
N ≈ 2,000 kg × 9.81 m/s² = 19,620 N
The frictional force, [tex]F_f[/tex] = μ × N
The centripetal force, [tex]F_c[/tex] = m·v²/r
The car moves without slipping when [tex]F_f[/tex] = [tex]F_c[/tex]
Therefore, [tex]F_f[/tex] = 0.500 × 19,620 N = 2,000 kg × [tex]v_{max}[/tex]²/40.0 m
∴ [tex]v_{max}[/tex] = √(0.500 × 19,620 N × 40.0 m/2,000 kg) ≈ 14.007 m/s
Therefore, the velocity with which the car moves, v < [tex]v_{max}[/tex]
The cars centripetal acceleration, [tex]a_c[/tex] = v²/r
∴ [tex]a_c[/tex] = (10.0 m/s)²/40.0 m = 2.5 m/s²
The cars centripetal acceleration as it goes round the turn, [tex]a_c[/tex] = 2.5 m/s².
Which type of reactions usually happens slowest?
Answer:
option b is correct..................
What is the relationship between electric field lines and equipotential lines that you observed in doing the lab
Answer:
Explained below
Explanation:
Generally speaking, we know in physics that Electric field lines are lines which usually start at positive charges and deflect away from them to terminate at the negative charges. Meanwhile Equipotential lines are lines that are used to connect points located on the same electric potential.
Finally, in conclusion, electric field lines are usually lines that go through in a perpendicular manner across every equipotential lines.
A parallel combination of a 1.47 μF capacitor and a 2.95 μF capacitor is connected in series to a 4.89 μF capacitor. This three‑capacitor combination is connected to a 15.5 V battery. Determine the charge on each capacitor.
Answer:
a. i. 35.96 μC b. i. 11.98 μC ii. 24.04 μC
Explanation:
We need to find the total capacitance of the system C.
The total capacitance of the parallel combination of a 1.47 μF capacitor and a 2.95 μF capacitor is C' = 1.47 μF + 2.95 μF = 4.42 μF.
C' = 4.42 μF is in series with the 4.89 μF capacitor and for a series combination of capacitors, we have the total capacitance, C from
1/C = 1/4.42 μF + 1/4.89 μF
1/C = (4.42 μF + 4.89 μF)/(4.42 μF × 4.89 μF)
1/C = 9.31 μF/21.6138 μF²
C = 21.6138/9.31 μF
C = 2.32 μF
So, the total charge in the circuit Q = CV where C = total capacitance = 2.32 μF and v = voltage = 15.5 V
So, Q = CV
Q = 2.32 μF × 15.5 V
Q = 35.96 μC
i. The charge on the 4.89 μF capacitor
Since the 4.89 μF is in series with C', the total charge flowing i the circuit is the total charge in the 4.89 μF capacitor. So, its charge Q = 35.96 μC
b. The charge in the 1.47 μF and 2.95 μF capacitors.
To find the charge in the 4.89 μF and 2.95 μF capacitors, we need to find the voltage across the combined parallel combination of a 1.47 μF capacitor and a 2.95 μF capacitor. The voltage, V' across the 4.89 μF capacitor, since Q = CV', V' = Q/C = 35.96 μC/4.89 μF = 7.35 V
So, the voltage V" across the combined parallel combination of a 1.47 μF capacitor and a 2.95 μF capacitor, C' is V" = 15.5 V - V' (since V' + V" = 15.5 V).
So, V" = 15.5 V - V'
V" = 15.5 V - 7.35 V
V" = 8.15 V
i. The charge on the 1.47 μF capacitor
Using Q' = CV" where Q' = charge across capacitor, C = 1.47 μF and V" = 8.15 V.
So, Q' = CV"
Q' = 1.47 μF × 8.15 V
Q' = 11.98 μC
ii. The charge on the 2.95 μF capacitor
Using Q" = CV" where Q' = charge across capacitor, C = 2.95 μF and V" = 8.15 V.
So, Q" = CV"
Q" = 2.95 μF × 8.15 V
Q" = 24.04 μC
A cricketer throws a ball sideways with an initial velocity of 30 m/s. She releases the ball from a height of 1.3m. Calculate how far the ball travels before hitting the ground.
Answer:
78.34
Explanation:
1.3/30=78.3m
Pls help asap!!
A bucket contains hot water at 95°c. A man wants to bath with water at 40°c. What is the ratio of the mass of hot water to the mass of cold water that he needs.
Answer:
55
Explanation:95-40=55
i hope i did the math right if i didnt please tell me
Two astronomy students travel to South Dakota. One stands on Earth’s surface and enjoys some sunshine. At the same time, the other descends into a gold mine where neutrinos are detected, arriving in time to detect the creation of a new radioactive argon nucleus. Although the photon at the surface and the neutrinos in the mine arrive at the same time, they have had very different histories. Describe the differences.
Answer:
The photon takes millions of years to reach the Surface of the sun while the Neutrinos travelling at the speed of light reaches the surface of the sun in approximately 2 seconds
The Photon is million year old while the neutrino is just some minutes old as observed by the student .
Explanation:
Although The Photon ( sunshine from the sun's surface ) heating up the student standing on the Earth's surface and the neutrinos discovered by the other student inside the gold mine are both formed in the Sun's core.
The difference between both are
The photon takes millions of years to reach the Surface of the sun while the Neutrinos travelling at the speed of light reaches the surface of the sun in approximately 2 seconds
The Photon is million year old while the neutrino is just some minutes old as observed by the student .
Write down the role played by four digestive juices in digestion and the
organs which secrete them.
Answer:
Digestive juices secreted by various organs such as salivary glands in the mouth, stomach, liver and pancreas help in the process of digestion of food. Saliva secreted by the salivary glands in the mouth aids in the breakdown of starch present in the food to simple sugar
Explanation: