Answer:

Explanation:
Total internal reflection can happen when light goes from a medium with higher refractive index (in this case, glass) to a medium with lower refractive index (in this case, water).
Snell's Law tells us that
, where the <em>i</em> stands for incident (in this case, glass) and the <em>r</em> for refracted (in this case, water). We want to know when
, that is, when
, and this happens when the incident angle is:

Which for our values means:

Answer: Electromagnetism and sound
The variable that changes is the period of the motion.
<h3>What is simple harmonic motion?</h3>
The term simple harmonic motion refers to a regular repeating motion. The acceleration of the SHM is always directed towards the center. The spring is an example of a system undergoing simple harmonic motion.
From the description in the question, the variable that changes is the period of the motion.
Learn more about simple harmonic motion: brainly.com/question/17315536
Answer:
A permanent magnet creates a magnetic field at all points in the surrounding region.
An electric current in a conductor creates a magnetic field at all points in the surrounding region.
A moving electric charge creates a magnetic field at all points in the surrounding region.
Explanation:
Magnet field is a region around the magnet in which the magnetic force can be experienced. A magnet has two poles: North pole and South pole. A Magnetic field originates from north pole and ends at south pole.
Magnets are of two types: Permanent magnet and temporary magnet.
A moving charge produces magnetic field. A stationary charge can not produce a magnetic field.
The rate of flowing charge constitutes an electric current. If the cardboard is placed around the current carrying conductor and the iron fillings spread around the cardboard then the iron nails get stick to it. It means that a current carrying conductor creates a magnetic field around it.
Therefore, the true statements from the given statements are as follows;
A permanent magnet creates a magnetic field at all points in the surrounding region.
An electric current in a conductor creates a magnetic field at all points in the surrounding region.
A moving electric charge creates a magnetic field at all points in the surrounding region.
Answer:
Explanation:
She's correct but doesn't mean the wagon cannot put into motion. The force that she applied on the wagon, according to Newton's 2nd law, would have generated an acceleration, which translates into motion. The reaction force the wagon applies on her due to Newton's 3rd law, would not hinder its own motion.