Answer:
Correct answer is A.
Explanation:
Frequency is the number of oscillations that a wave have per unit time. Since time is measured in seconds, the wave with the highest frequency must register the highest number of oscillation per second. Hence, correct answer is A.
Halogens is defined as the group of 7 periodic table. As, every periodic table contains 7 valence electrons and they only need 1 more to complete an outer shell, that is why they are extremely reactive. And according to the law that recurring patterns of the properties of elements arise when they are arranged in order of increasing atomic number. As the halogen all act very similarly with each other in chemical reaction, it is true.
Answer:
56°
Explanation:
First calculate 

The interplanar spacing can be calculated from:

The diffraction angle is determined from:

Solve for 

The diffraction angle is:

Answer:
A- Physical, B- Chemical, C- chemical, D- Physical
Explanation:
A is physical because you can see it changing its form is changing.
B is Chemical because a new substance is formed creating the orange color of rust.
C is a Chemical reaction because it is being broken down so the banana itself is changing not just how we see it.
D is physical because we are just changing the shape/ size of the item, not anything to do with its substances.