define rectilinear propagation of light​

Answer:

Calculate the wavelength associated with an electron with energy 2000 eV.

Sol: E = 2000 eV = 2000 × 1.6 × 10–19 J

Answer:

E = 1.711 MeV

Explanation:

From the law of the conservation of energy:

[tex]K.E_{e}+K.E_p + E_{e}+E_{p} = 2 E[/tex]

where,

[tex]K.E_e=K.Ep=[/tex] the kinetic energy of positron and electron = 1.2 MeV

[tex]E_e=E_p =[/tex] Rest energy of the electron and the positron = 0.511 MeV

E = Energy of Photon = ?

Therefore,

[tex]1.2\ MeV + 1.2\ MeV + 0.511\ MeV + 0.511\ MeV = 2E\\\\E = \frac{3.422\ MeV}{2}\\\\[/tex]

E = 1.711 MeV

Answer: 0.390625 grams

Explanation:

A half-life of an element is the amount of time that it takes for half the mass of the element to decay.

Gold-198 having a half-life of 2.5 days therefore means that every 2.5 days, the mass is cut in half.

If there are 20 days, find out how many half-life periods there are:

= 20 / 2.5

= 8 periods

The half life is:

= Original mass * 0.5^number of half-life periods

= 100 * 0.5⁸

= 0.390625 grams

Answer:

B) The current of the entire circuit is lowered.

Explanation:

There are two ways in which a resistor can be connected in a circuit;

i) Series: In a series connection, resistors are connected end to end. In this arrangement, the current passing through each resistor is the same while the potential difference across each resistor is different.

ii) Parallel: In a parallel connection, resistors are connected to  common junctions. In this arrangement, the potential difference across each resistor is the same while the current across each resistor varies.

In a series circuit, the effective resistance is the algebraic sum of resistance of all the resistors connected in series. Hence, if a large resistor is connected in series, the effective resistance of the circuit is greatly increased.

Since the voltage is given by;

V=IR (Ohm's law)

Where R is the effective resistance

Then;

I = V/R

If R becomes very large due to a large resistance connected in series, then the current of the entire circuit is lowered.

Answer:

Solution given:

Radius of small sphere[r]=5cm=0.05m

Radius of large sphere[R]=10cm=0.1m

capacitance of small sphere[c]=4πε0r

=[tex]4π*8.85×10^{-12}×0.05=5.56*10^{-12}F[/tex]

Charge for small sphere[Q1]=100C

Charge for small sphere[Q2]=50C

Potential difference [V1]=[tex] \frac{charge}{capacitance}=\frac{100}{5.56*10^{-12}}=1.8×10^{13}[/tex]V

.

again

capacitance of small sphere[C]=4πε0R

=[tex]4π*8.85×10^{-12}×0.1=1.11*10^{-11}F[/tex]

Potential difference [V2]=[tex] \frac{charge}{capacitance}=\frac{50}{1.11*10^{-11}}=4.5×10^{12}[/tex]V

Now

Loss of energy:

[tex] \frac{cC(V1-V2)^{2}}{2(c+C)}[/tex]

=[tex] \frac{5.56*10^{-12}*1.11*10^{-11}(1.8*10^{13}-4.5*10^{12})^{2}}{2(5.56*10^{-12}+1.11*10^{-11})}[/tex]

=25Joule

Ship handling is both a science and an art. Science because it requires knowledge of various forces acting on the ship. Art because it requires the skills of an experienced navigator to use these forces in his favour. We may learn the science part from the various ship handling courses.

please give brainliest

Answer:

D

Explanation:

Answer:

The distance moved by the block is 1.34 m

Explanation:

Given;

initial velocity of the block, u = 3 m/s

angle of inclination, θ = 20⁰

The net horizontal force acting on the block;

∑Fx = - mgsinθ

Apply Newton's second law of motion, to determine the constant acceleration of the block.

∑Fx = ma

- mgsinθ = ma

-gsinθ = a

Apply the following Kinematic equation, to determine how far up, the block moved before coming to rest.

[tex]V_f^2 = V_i^2 + 2a(x_f -x_i)\\\\0 = V_i^2 + 2[-gsin \theta(x_f-0)]\\\\0 = V_i^2 - 2gsin \theta(x_f)\\\\ 2gsin \theta(x_f) = V_i^2\\\\x_f = \frac{V_i^2}{2gsin \theta} = \frac{(3)^2}{2 \ \times \ 9.8 \ \times \ sin(20)} = 1.34 \ m[/tex]

Therefore, the distance moved by the block is 1.34 m

Given :

A gerbil wheel has a radius of 3.2 inches. The gerbil can spin the wheel at a rate of 35 rotations per minute.

To Find :

The angular speed of the wheel in degrees per minute and the linear speed of wheel in inches per minute.

Solution :

Angular speed is given by :

[tex]\omega = 25\ rpm \\\\\omega = 25\times 360^o \ per \ minute\\\\\omega = 9000^o \ per \ minute[/tex]

Now, velocity is given by :

[tex]v = Radius\times \dfrac{RPM}{60\ sec/min}\times 2\pi\ rad/rev\\\\v = 3.2 \times \dfrac{35}{60}\times 2\pi\\\\v = 11.73\ m/s[/tex]

Hence, this is the required solution.

Answer:

Solid cylinder

Explanation:

because hollow may blow and just bounce

Answer:

awareness and honesty toward others

Answer:

force on the electron is upwards

Explanation:

The magnetic force is given by the relation

        F = q v x B

the bold indicates vectors, we can write the module of this expression

        F = q v  B sin θ

the direction of the force is given by the right hand rule.

If we have a positive charge, the flea points in the direction of velocity, in this case towards the inside of the page.

fingers extended in the direction of the magnetite field, in our case to the right and

the palm gives the direction of the force for a positive charge, for a negative charge it is in the opposite direction. The palm points downwards, so the force on the electron is upwards

Answer:

(1) By increasing the number of loops of wire around the iron core

(2) increasing the current or voltage.

Answer:

Copper

Explanation:

Copper is the least resistant because it is the best conductor of electricity in the options mentioned.

Answer:

I think it's B. Sound Waves

Answer: I think you have the correct answer. (I think it is false.)

Explanation: The Earth's magnetic field is mostly caused by electric currents in the liquid outer core. The Earth's core is hotter than 1043 K, the Curie point temperature above which the orientations of spins within iron become randomized. Such randomization causes the substance to lose its magnetization.

Answer:

Answer is option d

Explanation:

,Mark as brainlist

Answer:

the magnitude of the average contact force exerted on the leg is  3466.98 N

Explanation:

Given the data in the question;

Initial velocity of hand v₀ = 5.25 m/s

final velocity of hand v = 0 m/s

time interval t = 2.65 ms = 0.00265 s

mass of hand m = 1.75 kg

We calculate force on the hand F[tex]_{hand[/tex]

using equation for impulse in momentum

F[tex]_{hand[/tex] × t = m( v - v₀ )

we substitute

F[tex]_{hand[/tex] × 0.00265  = 1.75( 0 - 5.25 )

F[tex]_{hand[/tex] × 0.00265  = 1.75( - 5.25 )

F[tex]_{hand[/tex] × 0.00265  = -9.1875

F[tex]_{hand[/tex] = -9.1875 / 0.00265  

F[tex]_{hand[/tex] = -3466.98 N

Next we determine force on the leg F[tex]_{leg[/tex]

Using Newton's third law of motion

for every action, there is an equal opposite reaction;

so, F[tex]_{leg[/tex] = - F[tex]_{hand[/tex]

we substitute

F[tex]_{leg[/tex] = - ( -3466.98 N )

F[tex]_{leg[/tex] = 3466.98 N

Therefore, the magnitude of the average contact force exerted on the leg is  3466.98 N

Answer:

convex       f = 33 cm

concave     f = -33 cm

Explanation:

In geometric optics the focal length of a lens is given by

         [tex]\frac{1}{f} = ( n-1) \ (\frac{1}{R_2} - \frac{1}{R_1} )[/tex]

where n is the refractive index of the medium, R₁ and R₂   are the focal lengths on each side of the lens.

In this case one of the sides is flat so its focal length is infinite, if the lens is convex the focal length is positive, convergent lens and if it is concave the focal length is negative, divergent lens.

         [tex]\frac{1}{f} = (n-1) \ \frac{1}{R}[/tex]

the refractive index of the glass is n = 1.5

let's calculate

         1 / f = (1.5 -1) 1 / 16.5

         1 / f = 0.03030

          f = 33 cm

convex       f = 33 cm

concave     f = -33 cm

Answer:

a = 0.1962 m/s^2

Explanation:

The magnitude of kinetic friction exerted is given by

[tex]F_k=\mu_kN[/tex]

Where, μ_k= coefficient of kinetic friction= 0.02 and N = reaction force = mg

Where m= mass = 30 Kg and, g is acceleration due to gravity =9.81 m/s^2

F_k=0.02×30×9.81 =5.886 N

Now, since, there is no applied force this kinetic friction force will cause acceleration of the child

⇒ ma = F_k

here, a is the acceleration

⇒30a = 5.886

⇒ a = 0.1962 m/s^2

Answer:

upward

Explanation:

In the electromagnetic system of force if the direction of motion of proton does not changes it means that the electric and magnetic forces are such a ways that they are cancelling each other's effect.

Since, electric field lines will exert a force on the proton to the west, hence, the magnetic force must force it to the east. It is well known that magnetic force acts perpendicular to the direction of magnetic field.  magnetic field should point upward direction.

Answer:

Explanation:

The law is about how object will be deformed when certain amount force is  applied. Elastic limit is a point where object will not return its previous shape after being deformed

Answer:

In particle physics, a lepton is an elementary particle of half-integer spin (spin 1⁄2) that does not undergo strong interactions.[1] Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutral leptons (better known as neutrinos). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium, while neutrinos rarely interact with anything, and are consequently rarely observed. The best known of all leptons is the electron.

Complete question is;

At one instant, v = (−2.00 i^ +4 .00 j^ − 6.00 k^)m/s is the velocity of a proton in a uniform magnetic field B = (2.00 i^ − 4.00 j^ +8 .00 k^) mT. At that instant, what are;

(a) the magnetic force acting on the proton, in unit-vector notation

(b) the angle between the velocity and magnetic field

Answer:

A) F = [1.28 × 10^(-21)] i^ + [6.4 × 10^(-22)] j^

B) θ = 151.02°

Explanation:

A) Since the unit of magnetic field is given in mT, let's convert it to T.

Thus;

B = (0.002 i^ − 0.004 j^ + 0.008 k^) T

Formula for the magnetic force is;

F = qVB

Where q = 1.6 × 10^(-19) C

Since V and B are in vector notation, the way to multiply it is;

(v_y•B_z - v_z•B_y)i^ + (v_z•B_x - v_x•B_z) j^ + (v_x•B_y - v_y•B_x) k^

Thus;

F = 1.6 × 10^(-19)((v_y•B_z - v_z•B_y)i^ + (v_z•B_x - v_x•B_z) j^ + (v_x•B_y - v_y•B_x) k^)

Plugging in the relevant values;

F = 1.6 × 10^(-19)[{(4 × 0.008) - (-6 × -0.004)} i^ + {(-6 × 0.002) - (-2 × 0.008)} j^ + {(−2 × -0.004) - (4 × 0.002)} k^]

Multiplying out gives;

F = [1.28 × 10^(-21)] i^ + [6.4 × 10^(-22)] j^

B) Angle between the 2 vectors gotten for the velocity and magnetic field is given by the formula;

Cos θ = (a•b)/(|a| × |b|)

(a•b) = (−2.00 i^ + 4.00 j^ − 6.00 k^) • (0.002 i^ − 0.004 j^ + 0.008 k^)

>> (2 × 0.002) + (4 × -0.004) + (-6 × 0.008) = -0.06

|a| = √((-2)² + (4)² + (-6)²)

|a| = √56

|b| = √((0.002)² + (-0.004)² + (0.008)²)

|b| = 0.009165

Thus;

Cos θ = -0.06/(0.009165 × √56)

Cos θ = -0.8748

θ = cos^(-1) -0.8748

θ = 151.02°

Answer:

Explanation:

it would be 3 because ju divide 12 by 4

Answer:

b is the answer of this qs

Answer:

a: 0.25 ohms

Explanation:

The resistance of the circuit can be calculated by using Ohm's Law:

[tex]V = IR\\\\R = \frac{V}{I}[/tex]

where,

R = Resistance of the circuit = ?

V = Voltage = 12 volts

I = Current = 48 A

Therefore,

[tex]R = \frac{12\ V}{48\ A} \\\\R = 0.25\ ohms[/tex]

Hence, the correct option is:

a: 0.25 ohms