Answer:
explanation of this effect is the photoelectric effect
Explanation:
Let's describe the process, when light of large wavelength falls, this implies a small energy, according to Planck's equation
E = h f = [tex]\frac{h \ c}{ \lambda}[/tex]
the energy of the photons is not enough to carry out an electronic transition between two states of the material, when we decrease the wavelength (the energy of the photons increases), the point is reached where the energy of the beam is equal to some energy of a transition, by which the electrons are promoted and since we can see a certain charge, as the atoms are neutral, some electrons must be removed from the material, this is represented in the macroscopic case as the work function of the material, consequently a unbalanced load that is what we can measure.
When we increase the lightning intensity, what we do is that we increase the number of photons and if each photon can remove an electron, by removing the electrons the difference between it and the positive charge (fixed in the nuclei) increases.
We can analyze the interaction of the photon and the electron as a particular collision.
The explanation of this effect was made by Einstein in his explained of the photoelectric effect
help, it's an emergency !!!!!!!
What happens when you move two
objects far apart from each other?
A. The force of gravity increases.
B. The force of gravity decreases.
C. Distance does not affect the force of gravity.
D. The friction between the two objects will increase.
Answer:
b
Explanation:
A uniform 140 g rod with length 57 cm rotates in a horizontal plane about a fixed, vertical, frictionless pin through its center. Two small 30 g beads are mounted on the rod such that they are able to slide without friction along its length. Initially the beads are held by catches at positions 11 cm on each sides of the center, at which time the system rotates at an angular speed of 23 rad/s. Suddenly, the catches are released and the small beads slide outward along the rod. Find the angular speed of the system at the instant the beads reach the ends of the rod. Answer in units of rad/s.
Answer:
The correct answer is "12 rad/s"
Explanation:
The given values are,
Mass of rod,
M = 140 g
i.e.,
= 0.14 kg
Length,
L = 57 cm
i.e.,
= 0.57 m
Mass of beads,
M = 30 g
i.e.,
= 0.03 kg
Angular speed,
r = 11 cm
i.e.,
= 0.11 m
Now,
The inertia of rods will be:
= [tex]\frac{1}{12}ML ^2[/tex]
On substituting the values, we get
= [tex]\frac{1}{12}\times 0.14\times (0.57)^2[/tex]
= [tex]0.0037905 \ kg-m^2[/tex]
The inertia of beads will be:
= [tex]mr^2[/tex]
On substituting the values, we get
= [tex]0.03\times (0.11)^2[/tex]
= [tex]0.000726 \ kg-m^2[/tex]
The total inertia will be:
= [tex]Inertia \ of \ rods+Inertia \ of \ beads[/tex]
= [tex]0.0037905 + 0.000726[/tex]
= [tex]0.0045165 \ kg-m^2[/tex]
now,
The angular speed of the system will be:
⇒ [tex]L_1w_1=L_2w_2[/tex]
On substituting the values in the above equation, we get
⇒ [tex]0.0045165\times 23 = (0.0037905 + (0.03\times 0.285^2)\times 2 )\times w_2[/tex]
⇒ [tex]0.1038795 = 0.0037905 + (0.00243675\times 2 )\times w_2[/tex]
⇒ [tex]w_2 = 12 \ rad/s[/tex]
What is the acceleration of a car at rest that speeds up to 75m/s over 25 seconds?
A. -3.0m/s/s
B. 75 m/s/s
C. 3.0 m/s/s
D. 25 m/s/s
E. Not enough data is given
How to explain third law when a boat is moving away from a paddock when a women’s feet is on the paddock and the boat
Answer:
According to Newton's third law of motion, for every action, there is an equal and opposite reaction. When the man jumps from a boat, he applies force on the boat due to which boat moves backward. An equal force is exerted by the boat on the man which helps the man to jump out of the boat.
Three cylindrical wires, 1, 2, and 3 are made of the same materialand have resistances R1, R2, and R3, respectively. Wires 1 and 2 have the same lengthbut diameter of wire 2 is twice that of wire 1. Wires 2 and 3 have the same diameterbut length of wire 3is twice that of wire 2.
1. Rank the wires according to their resistances, greatest first.
A. R1> R2> R3R1
B. R1> R3> R2R2
C. R2> R1> R3R3
D. R2> R3> R1
E. R3> R1> R2
F. R3> R2> R1Q2.
2. If same voltage is applied across each of the wires, which one will dissipate heat at the highest rate
Answer:
1) R₁ > R₃ > R₂ correct B , 2) the wire that dissipates the most is wire 2
Explanation:
1) The resistance of a wire is given by the expression
R = [tex]\rho \ \frac{l}{A}[/tex]
where ρ is the resistivity of the material, l the length of the wire and A the area of the wire
The area is given by
A = π r² = π d² / 4
we substitute
R = (ρ 4 /π) [tex]\frac{l}{d^2}[/tex]
the amount in parentheses is constant for this case
let's analyze the situation presented, to find the resistance of each wire
* indicate l₁ = l₂ and d₂ = 2 d₁
the resistance of wire 1 is
R₁ = (ρ 4 /π) [tex]\frac{l_1}{d_1^2}[/tex]
the resistance of wire 2 is
R₂ = (ρ 4 /π) \frac{l_2}{d_2^2}
R₂ = (ρ 4 /π) [tex]\frac{l_1}{ (2 d_1)^2}[/tex]
R₂ = (ρ 4 /π ) [tex]\frac{l_1}{d_1^2}[/tex] ¼
R₂ = ¼ R₁
* indicate that d₂ = d₃ and l₃ = 2 l₂
R2 = (ρ 4 /π) [tex]\frac{l_2}{d_2^2}[/tex]
the resistance of wire 3 is substituting the indicated condition
R3 = (ρ 4 /π 2) \frac{l_3}{d_3^2}
R3 = (ρ 4 /π) [tex]\frac{2 \ l_2}{d_2}[/tex]
R3 = 2 R₂
let's write the relations obtained
R₁ = (ρ 4 /π) [tex]\frac{I_1}{ d_1^2}[/tex]
R₂ = ¼ R₁
R₃ = 2 R₂
let's write everything as a function of R1
R₁ =(ρ 4 /π) [tex]\frac{l_1}{d_1^2}[/tex]
R₂ = ¼ R₁
R₃ = ½ R₁
the resistance of the wire in decreasing order is
R₁ > R₃ > R₂
2) The power dissipated by a wire is
P = V I
the voltage is
V = I R
I = V / R
substituting
P = V² / R
therefore the power dissipated by each wire is
wire 1
P₁ = V² / R₁
wire 2
P₂ = V² / R₂
P₂ = [tex]\frac{V^2}{ \frac{1}{4} R_1}[/tex]
P₂ = 4 P₁
wire 3
P₃ = V² / R₃
P₃ = [tex]\frac{V^2}{ \frac{1}{2} R_1}[/tex]
P₃ = 2 P₁
Therefore, the wire that dissipates the most is wire 2
6. If you lift an object, to find the work you did on the object, you must find
the__ first
a velocity
b. power
c. acceleration
d. weight
What is Na2SO4?
Help pleaseeee.
A) how many cm³ are there in 0.08L?
B) How many dm³ are there in 750mL?
Answer:
A) 80 cm³
B) 0.75 dm³
Explanation:
I hope this help❤️
Find the velocity of a dolphin that swims 55 m in 5.0 s.
Answer: 11 m/s
Explanation: velocity = distance /time = 55 m /5.0 s
Answer:40km/h
Explanation:
The microwaves produced inside a microwave have a wavelength of 12.0m and a frequency of 25Hz. At what speed do the microwaves travel in units of m/s ?
Answer: 300 m/s
Explanation:
The equation for finding wave speed is the wavelength times the frequency which would be
12.0mx 25hz=300m/s
How much work is done by 15 kW engine during 3.5 min? Explain the answer if you can plz
Answer:
W = 3.15 · 10⁶ J
Explanation:
We know that power is calculated using the formula:
P = W/twhere P = power (W), W = work (J), and t = time (s)We can derive a formula for work using this formula by multiplying t to both sides of the equation.
W = PtLet's convert 15 kW to W.
15 kW → 15,000 WLet's convert 3.5 min to s.
3.5 min → 210 sSubstitute these values into the formula for work and solve for W.
W = Pt W = (15,000 W) · (210 s) W = 3,150,000 J W = 3.15 · 10⁶ JThis is the amount of work done by a 15 kW engine in 3.5 minutes.
You want to use a metal bar as a resistor. Its dimensions are 1 by 3 by 13 units. To get the largest resistance from the bar, you should attach leads to the two opposite sides that have dimensions of 1 by 3 units. All configurations give the same resistance. 3 by 13 units. 1 by 13 units. None of the above.
Answer:
1 by 3 units
Explanation:
The resistance (R) of a conductor is given by the formula:
R = ρL / A
where L is the length of the conductor, ρ is resistivity and A is the cross sectional area.
Let us assume that the metal bar has a resistivity of ρ.
a) If the leads is attached to the two opposite sides that have dimensions of 1 by 3 units.
The length of the bar would be 13 units and the cross sectional area (A) would be = 1 * 3 = 3 units²
R₁ = ρL / A = ρ(13) / 3 = 13ρ / 3
b) If the leads is attached to the two opposite sides that have dimensions of 3 by 13 units.
The length of the bar would be 1 units and the cross sectional area (A) would be = 3 * 13 = 39 units²
R₂ = ρL / A = ρ(1) / 39 = ρ / 39
c) If the leads is attached to the two opposite sides that have dimensions of 1 by 13 units.
The length of the bar would be 3 units and the cross sectional area (A) would be = 1 * 13 = 13 units²
R₃ = ρL / A = ρ(3) / 13 = 3ρ / 13
Therefore we can see that the largest resistance is gotten If the leads is attached to the two opposite sides that have dimensions of 1 by 3 units
Which of the following is a conductor?
copper
water
aluminum
all of the above
Answer:
D all of the above
Explanation:
electricity moves easily through all of them and none of them prevent the flow of electricity
Which bond(s) shown are double bonds?
Answer:
in the diagram shown, Oxygen is the only one that has a double bond.
Explanation:
Chemical bonds are the way that electors are shared between atoms to form molecules whose energy is less than the energy of individual atoms.
A graphical way to show these electrons is to represent them by point in the atoms. Every other point represents a shared bond or pair of electrons.
Therefore for simple bonds two electrons are drawn. For double bonds four electrons and for triple bonds six electrons.
Therefore, in the diagram shown, Oxygen is the only one that has a double bond.
who compose the Ghana national anthem
Answer:
Philip Gbeho
Explanation:
How much heat does it lose to change 126 g of water from 67°C to 37°C?
Explanation:
convert gram into kg q means amount of heat lost
Please help
The period of an oscillation is measured to be 0.0833 seconds. What is
the frequency of this oscillation? *
1.0833 Hz
0.287 Hz
9.8 Hz
12 Hz
0.007 Hz
Answer:
your
answer is
12.004
PLZ HELP ILL GIVE RBAINLIEST
Which of the following factors can affect the strength of electric or magnetic fields? (YOU MAY SELECT MORE THAN ONE ANSWER)
Strength of the magnet/electric charge
The material that is creating the field
The mass of the object creating the field
The distance from the source of the field
Can light have inertia??
Answer:
Yes.
Explanation:
Yes Light has inertia, since inertia is in units of mass.
After landing on an unexplored Klingon planet, Spock tests for the direction of the magnetic field by firing a beam of electrons in various directions and by recording the following observations:1. Electrons moving upward feel a magnetic force in the northwest direction.2. Electrons moving horizontally toward the north are pushed downward.3. Electrons moving horizontally toward the southeast are pushed upward.Mr. Spock therefore concludes that the magnetic field at this landing site is in which direction?A) toward the eastB) toward the northeastC) toward the southwestD) toward the southeastE) toward the west
Answer:
the correct one is C,
Explanation:
The magnetic force is given by the expression
F = q v x B
where the bold letters indicate vectors, we can find the modulus of this expression
F = q v B sin θ
The direction of the to the force with the rule of the right hand. The thumb applies in the direction of the speed, the fingers extended in the direction of the magnetic field and if the charge is positive the palm is in the direction of the force, if the charge is megative the force is in the opposite direction to the palm of hand.
Let's analyze the different situations presented; As the particles emitted are electrons, their charge is negative.
Situation 1. The thumb points upwards, the force is towards the NW as the charge is negative, the palm points towards the SE therefore the finger points towards the SOUTHWEST which must be the direction of the magnetic field
Situation 2. the electrons go horizontally to the north the thumb points in this direction, the force is downwards, therefore the palm points upwards, the extended fingers point to the WEST
Situation 3. the thumb points to the SE towards where the electrons move, the force is upwards the palm points to the SW, therefore the fingers extended points SOUTHWEST
As a result of situations 1 and 3 the magnetic field must point in the SOUTHWEST direction.
Situation 2 gives a different result because the component of the field that is directed to the south does not create exerts and therefore cannot be detected.
When checking the answers, the correct one is C
A human body consists of
Answer:
60% of the human adult body is water. According to H.H. Mitchell, Journal of Biological Chemistry 158, the brain and heart are composed of 73% water, and the lungs are about 83% water. The skin contains 64% water, muscles and kidneys are 79%, and even the bones are watery: 31%.
Explanation:
The human body stores chemical energy from digested food. Some of the chemical energy is converted into mechanical energy when the body moves. Which statement is best supported by this information?
The body does not convert chemical energy to thermal energy.
The body does not convert chemical energy to kinetic energy.
Digested food is a source of potential energy.
Digested food is a form of radiant energy.
Answer:
Your answer is c :)
Explanation:
Two resistors R1 = 3 Ω and R2 = 6 Ω are connected in parallel. What is the net resistance in the circuit?
Answer:
2ohms
Explanation:
the net resistance is given by
1/R=1/R1 +1/R2,we are supposed to find R
thus by making R the subject ....
R=R1•R2/R1+R2
R=3•6/3+6
R=18/9 =2Ohms
Three 5 Ohm resistors are connected in parallel to a 9 Volt power supply. What is the current through each resistor?
Answer:
I₁ = I₂ = I₃ = 12 A
Explanation:
Since the resistors are connected in parallel across a battery. Hence, the voltage across each of them will be the same, which will be equal to the voltage of the power supply. Since each resistor has the same resistance of 5 Ω. Therefore. the current across each resistor will also be the same. We can easily calculate these current values by the use of Ohm's Law, as follows:
[tex]V = IR\\I_{1}=I_{2}=I_{3}=\frac{V}{R} \\\\I_{1}=I_{2}=I_{3}=\frac{9\ Volt}{5 \Omega}\\\\[/tex]
I₁ = I₂ = I₃ = 12 A
given that two vectors A=i,2j-2k and B=6i+3j+2k find A +B
Answer:
7i, 5j, 0k
Explanation:
Add up the two vectors.
Add
i+i 1+6 = 7i
j+j 2+3 = 5j
k+k -2+2 = 0k
therefore A+B = (7i, 5j, 0k)
PLEASE HELP ME WITH ONE QUESTION
If 1000 J of heat energy is lost from a piece of hot metal which is placed into a cup of cool water, how much energy is gained by the water?
Answer:
1000J
Explanation:
According to the law of calorimetry;
Heat lost by cold substance = Heat gained by hot substance
If 1000 J of heat energy is lost from a piece of hot metal,
heat lost by hot substance = 1000J
Since we are to determine how much energy is gained by the water, using the law
Heat lost by hot metal = heat gained by the water
Hence heat gained by the water = 1000J
Which types of reactions are also redox reactions?
Answer:
Your ans is B)
Explanation:
Hope its right
if wrong firgive me
Two resistors R1 = 3 Ω and R2 = 6 Ω are connected in parallel. What is the net resistance in the circuit?
Answer:
"2Ω" is the net resistance in the circuit.
Explanation:
The given resistors are:
R1 = 3Ω
R2 = 6Ω
The net resistance will be:
⇒ [tex]\frac{1}{R_{net}} =\frac{1}{R_1} +\frac{1}{R_2}[/tex]
On substituting the values, we get
⇒ [tex]\frac{1}{R_{net}} =\frac{1}{3} +\frac{1}{6}[/tex]
On taking L.C.M, we get
⇒ [tex]\frac{1}{R_{net}} =\frac{2+1}{6}[/tex]
⇒ [tex]\frac{1}{R_{net}} =\frac{3}{6}[/tex]
⇒ [tex]\frac{1}{R_{net}} =\frac{1}{2}[/tex]
On applying cross-multiplication, we get
⇒ [tex]R_{net}=2 \Omega[/tex]
The amount of sliding friction depends on the
a. weight of the moving object and the type of surface that the
object slides across.
b. density and volume of the object.
c. acceleration and mass of the object.
d. density and mass of the object.
*help please
Answer:
c I think so do u know the formula for friction??friction? lkke kinetic friction