Answer:
correct answer is 1 and 3
Explanation:
In direct measurement with an instrument, the precision or absolute error of the instrument is given by its appreciation, in this case we see that the measurements have two decimal places, so the appreciation of the instrument must be 0.01 cm
Based on this appreciation, the valid measurements are 5.52 and 5.5.
the other two measurements have errors much higher than the assessment of the instrument, for which there must have been some errors in the measurement.
The correct answer is 1 and 3
Answer:
24km/h
Explanation:
go it right on ingenuity 2020
As we know from kinematics
So it will turn by 18 radian
Answer:
0.158 A.
Explanation:
Mass of gold deposited = 3 x 10^-3 kg
= 3 g
Molar mass = 196 g/mol
Number of moles = 3/196
= 0.0153 mol.
Faraday's constant,
1 coloumb = 96500 C/mol
Quantity of charge, Q = 96500 * 0.0153
= 1477.04 C.
Remember,
Q = I * t
t = 2.59 hr
= 2.59 * 3600 s
= 9324 s
Current, I = 1477.04/9324
= 0.158 A.
0.158A
Using Faraday's first law of electrolysis which states that the mass(m) of a substance deposited or liberated at any electrode is directly proportional to the quantity of charge or electricity (Q) passed. i.e
m ∝ Q
m = Z Q
Where;
Z is the proportionality constant called electrochemical equivalent.
Faraday also observed that when 1 Faraday of electricity is equivalent to 96500C of charge.
Also,
Quantity of charge (Q), which is the product of current (I) passing through and the time taken (t) for the electrolysis, is given by;
Q = I x t; ----------------------(i)
With all of these in place, now let's go answer the question.
Since the gold ions carry one elementary unit of positive charge, now let's write the cathode-half reaction for gold (Au) as follows;
Au⁺ + e⁻ = Au ---------------------(ii)
From equation (ii) it can be deduced that when;
1 Faraday (96500C) of electricity is passed, 1 mole of Au forms ( = 197 grams of Au) [molar mass of Au = 197g]
Then, 3.00 x 10⁻³ kg (= 3 g of Au) will be formed by 3g x 96500C / 197g = 1469.5C
Therefore, the quantity of charge (Q) deposited is 1469.5C
Substitute this value (Q = 1469.5C) and time t = 2.59h (= 2.59 x 3600 s) into equation (i);
Q = I x t
1469.5 = I x 2.59 x 3600
1469.5 = I x 9324
Solve for I;
I = 1469.5 / 9324
I = 0.158A
Therefore, the current in the cell during that period is 0.158A
Note:
1 mole of gold atoms = 176g
i.e the molar mass of gold (Au) is 176g
The intensity of sounds is dependent on the square of the amplitude, not the frequency. Therefore, the intensity of sound remains the same when frequency is altered but the amplitude is constant. When the amplitude is quadrupled, the intensity of the sound becomes sixteen times greater.
In the field of physics, the intensity of a sound wave is defined as the power per unit area carried by the wave. This question involves calculating the change in sound wave intensity when the frequency and displacement amplitude of the source are altered.
(a) When the frequency is increased to 2.20 kHz while keeping the displacement amplitude constant, the intensity does not change, as the intensity in this case is not dependent on the frequency but on the square of the amplitude. Therefore, the intensity remains 0.750 W/m2.
(b) When the frequency is reduced to 0.250 kHz and the displacement amplitude is quadrupled, the intensity changes. Since the intensity of a sound wave is proportional to the square of the amplitude, by quadrupling the amplitude, the intensity will become 16 times greater (since 4 squared is 16). Hence, the new intensity will be 16 * 0.750 = 12 W/m2.
#SPJ12
Answer:
12.15°
Explanation:
Using Snell's law as:
Where,
is the angle of incidence ( 14.0° )
is the angle of refraction ( ? )
is the refractive index of the refraction medium (n=1.46)
is the refractive index of the incidence medium (n=1.27)
Hence,
Angle of refraction = = 12.15°
Answer:
M
Explanation: