Which quantity is a vector quantity?

A metal foil has a threshold frequency of 5.45×1014 hz . Which of the colors of visible light have enough energy to eject electr

trapecia [35]

Answer:

Green, blue, indigo and violet.

Explanation:

The velocity of a wave is given by

$v=f\lambda$

where

f = Frequency = $5.45\times 10^{14}\ Hz$

$\lambda$ = Wavelength

$\lambda=\frac{v}{f}\\\Rightarrow \lambda=\frac{3\times 10^8}{5.45\times 10^{14}}\\\Rightarrow \lambda=5.50459\times 10^{-7}\ m=550.459\times 10^{-9}\ m\\ =550.459\ nm$

The wavelength of the wave is 550.459 nm

Green light has wavelength which ranges from 500-565 nm.

So, the light which observed is green light and lower in wavelength than green light i.e., green, blue, indigo and violet.

8 0

3 years ago

Help with these below and the above. I will give brainliest and 20 points!

Juli2301 [7.4K]

#1

height from which it is dropped is 64.8 m

time taken to fall the object is

$h = v_y * t + 0.5 gt^2$

$64.8 = 0 + 0.5 * 9.8 * t^2$

$t = 3.64 s$

so it will take 3.64 s to drop

#2

Since the package is dropped from plane so the package and plane both will have same speed in horizontal direction so with respect to plane the package will always remain in same horizontal position.

Now here since the package is also moving downwards due to free fall so it will always seen as dropped down while we are watching it from the plane

The package appears to fall straight downward.

#3

Let the time trianglet is "t"

now in this interval of time if it falls down by 4 cm

$h = v_y *t + 0.5 gt^2$

$4 = 0 + 0.5* 9.8 * t^2$

$t^2 = \frac{4}{4.9}$

now in same time it covers horizontal distance

$d = v_x * t$

$4 = \sqrt{\frac{4}{4.9}} * v_x$

$v_x = 4.43 m/s$

now after two trianglet the horizontal position will be

$x = v_x * t$

$x = 4.43 * 2*\sqrt{\frac{4}{4.9}}$

$x = 8 cm$

$y = v_y * t + 0.5 g t^2$

$y = 0 + 0.5 * 9.8 * 4 * \frac{4}{4.9} = 16 cm$

so it is 8 cm to the right and 16 cm below

#3

Speed horizontal = 42 m/s

distance covered = 60 ft 6 inch

$d = 60.5 * 0.3048 = 18.44$

time taken to cover the distance

$x = v* t$

$18.44 = 42 * t$

$t = 0.44 s$

now the distance by which it is dropped

$y = \frac{1}{2}gt^2$

$y = 0.5 *9.8*0.44^2 = 0.944 m$

#4

here the velocity of projectile will increase when it will fall under gravity

So here it we can see initially it is moving up against the gravity so its speed will increase but after that its speed will increase when it starts falling down

So the correct answer is Between B to C

#5

when x coordinate is 1000

time taken to reach that point will be

$x = v_x * t$

$1000 = 50 * t$