Answer:

Explanation:
We are given that


d=1.9 cm=
Using 1m=100 cm
We have to find the electric field strength.

Using the formula





Mass of electron,m

Substitute the values


Answer:
70 m.
Explanation:
Given,
Frequency, f = 20 HZ
speed of sound, v = 1400 m/s
wavelength of the waves = ?
we know,
v = f λ



Hence, the wavelength of the wave is equal to 70 m.
Answer:
27.1m/s
Explanation:
Given parameters:
Height of the building = 30m
Initial velocity = 12m/s
Unknown:
Final velocity = ?
Solution:
We apply one of the kinematics equation to solve this problem:
v² = u² + 2gh
v is the final velocity
u is the initial velocity
g is the acceleration due to gravity
h is the height
v² = 12² + (2 x 9.8 x 30)
v = 27.1m/s