The diagram below illustrates the law of reflection.

According to the law of reflection, which statement must be true?

The measure of angle A equals the measure of angle B.
The measure of angle B equals the measure of angle C.
The measure of angle A equals the measure of angle C.
The measure of angle B equals the measure of angle D.

Then angle A + angle B = 90 degrees. We can say angles A and B are complementary. Supplementary Angles - Two angles whose measures add up to 180 degrees. Supplementary angles can be placed so that they form a straight line.

The measure of angle B equals the measure of angle C. Explanation: When a ray of light falls on a smooth polished surface and the light ray bounces back, it is called the reflection of light

Explanation:

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answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.