All categories

3 years ago

Plz help with atomic question giving brianly.

Physics

2 answers:

GalinKa [24]3 years ago

7 0

Answer:

The atomic number of an atom equals the number of protons in the nucleus of that atom. The atomic number of an element is always a positive integral value.

Explanation:

Eddi Din [679]3 years ago

6 0

Atomic number equals the number of protons or the number of electrons

hope this helps

You might be interested in

PLEASE HELP!!!!!

never [62]

Answer:

The answer is A

Explanation:

When a rockets thrusters push on the ground the ground pushes back on the rocket with equal force in the opposite direction. Hence the rocket takes off.

Newtons third law of motion states, for every action there is an equal and opposite reaction.

7 0

2 years ago

The electrons in the beam of a television tube have a kinetic energy of 2.20 10-15 j. initially, the electrons move horizontally

dalvyx [7]

(a) The electrons move horizontally from west to east, while the magnetic field is directed downward, toward the surface. We can determine the direction of the force on the electron by using the right-hand rule:
- index finger: velocity --> due east
- middle finger: magnetic field --> downward
- thumb: force --> due north
However, we have to take into account that the electron has negative charge, therefore we have to take the opposite direction: so, the magnetic force is directed southwards, and the electrons are deflected due south.

b) From the kinetic energy of the electrons, we can find their velocity by using
$K= \frac{1}{2}mv^2$
where K is the kinetic energy, m the electron mass and v their velocity. Re-arranging the formula, we find
$v= \sqrt{ \frac{2K}{m} }= \sqrt{ \frac{2 \cdot 2.20 \cdot 10^{-15} J}{9.1 \cdot 10^{-31} kg} }=6.95 \cdot 10^7 m/s$

The Lorentz force due to the magnetic field provides the centripetal force that deflects the electrons:
$qvB = m \frac{v^2}{r}$
where
q is the electron charge
v is the speed
B is the magnetic field strength
m is the electron mass
r is the radius of the trajectory
By re-arranging the equation, we find the radius r:
$r= \frac{mv}{qB}= \frac{(9.1 \cdot 10^{-31} kg)(6.95 \cdot 10^7 m/s)}{(1.6 \cdot 10^{-19} C)(3.00 \cdot 10^{-5} T)}=13.18 m$

And finally we can calculate the centripetal acceleration, given by:
$a_c = \frac{v^2}{r}= \frac{(6.95 \cdot 10^7 m/s)^2}{13.18 m}=3.66 \cdot 10^{14} m/s^2$

5 0

3 years ago

Describe how excavations are done.

Mazyrski [523]

Answer:

It includes earthwork, trenching, wall shafts, tunneling and underground

Explanation:

4 0

3 years ago

A 2,700-kg truck runs into the rear of a 1,000-kg car that was stationary. The truck and car are locked together after the colli

Leto [7]

Answer:

6200 J

Explanation:

Momentum is conserved.

m₁ u₁ + m₂ u₂ = m₁ v₁ + m₂ v₂

The car is initially stationary. The truck and car stick together after the collision, so they have the same final velocity. Therefore:

m₁ u₁ = (m₁ + m₂) v

Solving for the truck's initial velocity:

(2700 kg) u = (2700 kg + 1000 kg) (3 m/s)

u = 4.11 m/s

The change in kinetic energy is therefore:

ΔKE = ½ (m₁ + m₂) v² − ½ m₁ u²

ΔKE = ½ (2700 kg + 1000 kg) (3 m/s)² − ½ (2700 kg) (4.11 m/s)²

ΔKE = -6200 J

6200 J of kinetic energy is "lost".

3 0

3 years ago

Magnet A doesn't have its poles labeled, but Magnet B has a clearly labeled north and south pole. If the

dusya [7]

Answer:

D: The side of Magnet A that's attracted to Magnet B's south pole must be Magnet A's north pole

Explanation:

D: The side of Magnet A that's attracted to Magnet B's south pole must be Magnet A's north pole because

1) opposite poles attract each other

2) similar poles repel each other

3)magnetic lines of force start at the north pole and end at the south pole

4 0

2 years ago

Read 2 more answers