Answer:

Explanation:
As we know that magnitude of two vectors is given as

here we know that
A = magnitude of vector A
B = magnitude of vector B
= angle between two vectors
so here we know that
A = 30 units
B = 40 units
angle = 90 degree
so we have



Answer:
The speed of the electron is 1.371 x 10⁶ m/s.
Explanation:
Given;
wavelength of the ultraviolet light beam, λ = 130 nm = 130 x 10⁻⁹ m
the work function of the molybdenum surface, W₀ = 4.2 eV = 6.728 x 10⁻¹⁹ J
The energy of the incident light is given by;
E = hf
where;
h is Planck's constant = 6.626 x 10⁻³⁴ J/s
f = c / λ

Photo electric effect equation is given by;
E = W₀ + K.E
Where;
K.E is the kinetic energy of the emitted electron
K.E = E - W₀
K.E = 15.291 x 10⁻¹⁹ J - 6.728 x 10⁻¹⁹ J
K.E = 8.563 x 10⁻¹⁹ J
Kinetic energy of the emitted electron is given by;
K.E = ¹/₂mv²
where;
m is mass of the electron = 9.11 x 10⁻³¹ kg
v is the speed of the electron

Therefore, the speed of the electron is 1.371 x 10⁶ m/s.
Answer:
In a way that is suitable or right for a particular situation or occasion: She didn't think we were appropriately dressed for a wedding. Business leaders who acted appropriately were widely praised. See. appropriate.
Answer:
center of mass = −0.50 m
Explanation:
given data
mass m1 = 3.04 kg
distance xm = -8 m
mass m2 = 5.61 kg
distance xM = 3.56 m
solution
we get here center of mass for n mass of system that is express as
center of mass =
......................1
but we have only 2 particle system so we will get
center of mass =
.................2
put here value and we will get
center of mass = 
solve it we will get
center of mass = −0.50 m
Answer:
t = 8.33 minutes
Explanation:
given,
Speed of Light, v = 3 x 10⁸ m/s
distance between sun to Earth = 1.5 x 10¹¹ m
time taken to reach earth = ?
we know,
Distance = speed x time


t = 500 s
1 min = 60 s
now, 
t = 8.33 minutes
time taken by the light to reach earth is equal to 8.33 minutes.