Please help this is physics!!!

Under what condition will a glass lens placed in a transparent medium becomes invisible??

Viktor [21]

Answer:

A lens placed in a transparent liquid becomes invisible because when refractive index of the material of the lens is equal to the refractive index of the liquid in which lens is placed under this condition no bending of light takes place when it travels from liquid to the lens, so both will start behaving like both are same things.

Explanation:

hope it helps :))

5 0

3 years ago

An astronomer is observing a star which puzzles her. The lines in the star's spectrum indicates that the star is very hot and sh

Firlakuza [10]

Answer:

the stars which are red in color are cool.

Explanation:

The stars which has reddish color are cool in nature while those stars which has white and blue in color are very hot in nature. The stars change its color when they becomes hotter , first the star color reddish when they are cool but with increasing temperature it changes the color from reddish to orange then yellow. After yellow it turns green and finally get blue color when the stars are very very hot.

5 0

3 years ago

A 55.0-g piece of copper wire is heated, and the temperature of the wire changes from 19.0°C to 86.0°C. The amount of heat absor

Alinara [238K]

The specific heat of a metal or any element or compound can be determined using the formula Cp = delta H / delta T / mass. delta pertains to change. That is change in enthalpy and change in temperature. From the given data, Cp is equal to 343 cal per (86-19) c per 55 grams. This is equal to 0.093 cal / g deg. Celsius

4 0

3 years ago

An electron of mass 9.11×10−31 kgkg leaves one end of a TV picture tube with zero initial speed and travels in a straight line t

ki77a [65]

Explanation:

We will use the equations of constant acceleration to find out $a_{x}$ and time t.

As we know that the initial speed is zero. So

(a)

$v_{0x} = 0$

$x - x_{o} = 1.25$ × $10^{-2}$ m

$v_{x} = 3.3$ × $10^{6}$ m/s

$v^{2} _{x} = v^{2} _{x_{o} } + 2a_{x} (x - x_{o} )$

$a_{x} = \frac{v^{2} _{x} - v^{2} _{ox} }{2(x - x_{o}) }$

= $\frac{(3.3 * 10^{6})^{2} - 0 }{2(1.25 * 10^{-2}) }$

= 4.356× $10^{14}$ m/s²

(b)

$v_{x} = v_{ox} + a_{x}t$

$t = v_{x} - vo_{x}/a_{x}$

$t = \frac{3.00 * 10^{6} }{4.356*10^{14} }$ = 6.8870× $10^{-9}$ s

(c)

Σ $F_{x} = ma_{x}$

= (9.11× $10^{-31}$ )(4.356× $10^{14}$ m/s²)

= 3.968× $10^{-16}$ N

6 0

3 years ago

The focal length of the lens of a simple camera is 40.0 mm. how far must the lens be moved to change the focus of the camera fro

Minchanka [31]

.05 cm far must the lens be moved to change the focus of the camera from a person 25 m away to one that is 4.0 m away

The focal length of a thin lens in air is the separation between its major foci, also known as focal points, and its center. The focal length is the distance at which a beam of collimated light will be concentrated to a single spot for a converging lens (for instance, a convex lens).

If v is the image distance in the first scenario

1 / v - 1 / -25 = 1 / .05

1 / v = 1 / .05 - 1 / 25

= 20 - .04 = 19.96

v = .0501 m = 5.01 cm

The second instance

u = 4 ,

1 / v - 1 / - 4 = 1 / .05

1 / v = 20 - 1 / 4 = 19.75

v = .0506 = 5.06 cm

Therefore, the lens must be advanced by 5.06 - 5.01 =.05 cm.

Learn more about lens here brainly.com/question/17086993

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4 0

1 year ago