Ask question

Ask question

All categories

3 years ago

7

1)A ________ mirror can take far-away light and focus it so that the object being viewed, such as the moon or a star, can be see

n as if it were much closer.
A. flat
B. convex
C. concave
D. diffracting

2)A magnifying lens permits sunlight to travel through it and come to a focus on the other side. What type of lens would have this effect?
A.flat B.convex C.concave D.diffracting

3)Due to the Doppler effect, if an ambulance had its siren on and was moving towards you, the pitch you would hear would be ________ the pitch the ambulance driver would hear.
A.lower than B.higher than C.the same as D.It would depend on the amplitude of the siren's sound waves.

1 answer:

kirza4 [7]3 years ago

4 0

D), C), A) should be right

You might be interested in

A step index fiber has a numerical aperture of NA = 0.1. The refractive index of its cladding is 1.465. What is the largest core

Vladimir [108]

Answer:

diameter = 9.951 × $10^{-6}$ m

Explanation:

given data

NA = 0.1

refractive index = 1.465

wavelength = 1.3 μm

to find out

What is the largest core diameter for which the fiber remains single-mode

solution

we know that for single mode v number is

V ≤ 2.405

and v = $\frac{2*\pi *r}{ wavelength} NA$

here r is radius

so we can say

$\frac{2*\pi *r}{ wavelength} NA$ = 2.405

put here value

$\frac{2*\pi *r}{1.3*10^{-6}} 0.1$ = 2.405

solve it we get r

r = 4.975979 × $x^{-6}$ m

so diameter is = 2 × 4.975979 × $10^{-6}$ m

diameter = 9.951 × $10^{-6}$ m

3 0

3 years ago

Two long straight wires are parallel and carry current in the same direction. The currents are 8.0 and 12 A and the wires are se

Bess [88]

A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any point is specified by two values, the direction and the magnitude; such that it is a vector field. Mathematically it is described as,

$B = \frac{\mu_0 I}{2\pi d}$

Here

$\mu_0$ = Permeability at free space constant

$I_{1,2}$ = Current at each object

d = Distance to the center point of the two object

Two magnetic field due to the current in the same directions then is,

$B = \frac{\mu_0 I_1}{2\pi d_1}+\frac{\mu_0 I_2}{2\pi d_2}$

Replacing,

$B = \frac{(4\pi *10^{-7})(8)}{2\pi (2*10^{-3})}+\frac{(4\pi *10^{-7})(12)}{2\pi (2*10^{-3})}$

$B = 8*10^{-4} +12*10^{-4}$

$B = 20*10^{-4}T$

Therefore the correct answer is E.

8 0

3 years ago

Scientists expected venus to have a large amount of water. however, little detectable water has been found anywhere on venus, ei

Citrus2011 [14]

The reason that says that Venus should have had water from the sources the same as the Earth, but all of those are gone is not a correct reason why Venus is dry. Venus is the hottest planet in the solar system because of the atmosphere it has. The atmosphere of Venus contains 95% of CO2 causing it be hot and dry.

4 0

3 years ago

A constant magnetic field passes through a single rectangular loop whose dimensions are 0.42 m x 0.54 m. The magnetic field has

olga_2 [115]

Answer:

$0.29887\ \text{V}$

Explanation:

A = Area = $0.42\times0.54\ \text{m}^2$

B = Magnetic field = 1.7 T

$\theta$ = Angle that magnetic field makes with the plane of the loop = $71^{\circ}$

t = Time = 0.42 s

EMF is given by

$\varepsilon=A\cos\theta\dfrac{dB}{dt}\\ =\dfrac{0.42\times 0.54\times\cos 71^{\circ}\times 1.7}{0.42}\\ =0.29887\ \text{V}$

The magnitude of the average emf induced in the loop is $0.29887\ \text{V}$ .

8 0

3 years ago

An exoplanetary system has two known planets. Planet X orbits in 290 days and Planet Y orbits in 145 days. Which planet is close

satela [25.4K]

Answer:

Planet Y

Rx = 1.587 Ry

Explanation:

Tx = 290 days

Ty = 145 days

Let the semi major axis of planet X is Rx and of plant Y is Ry.

According to the Kepler's third law of planetary motion

$\frac{T_{x}^{2}}{T_{y}^{2}}=\frac{R_{x}^{3}}{R_{y}^{3}}$

$\frac{290^{2}}{145^{2}}=\frac{R_{x}^{3}}{R_{y}^{3}}$

$4=\frac{R_{x}^{3}}{R_{y}^{3}}$

$1.587=\frac{R_{x}}{R_{y}}$

Rx = 1.587 Ry

So, planet Y is closest to star.

6 0

3 years ago