Answer:
<em>Answer is in the attachment</em>
Answer:
Uranium-238 undergoes alpha decay to form Thorium-234 as daughter product.
Explanation:
Alpha decay is indicative of loss of the equivalents of a helium particle emission. The reaction equation for this reaction is shown below:
→ 
I hope this explanation is clear and explanatory.
Explanation:
Physical change -
It refers to any change during any process , where there is no new substance is formed , is referred to as a physical change.
Any change in the state of matter is characterised under physical change.
Chemical change -
It refers to any change in a chemical process , where there is formation of any new substance , is referred to as a chemical change .
From the options given in the question,
1. Apple turning brown , on air exposure , is an example of chemical change .
2. The physical state of mercury is liquid , is an example of physical change .
3. phosphorus burns on exposed to air , is an example of chemical change .
4. The gas Neon is colorless at the room temperature , is is an example of physical change .
The pebbles become smooth and even because of erosion. the waves from the sea rub against the pebbles this is erosion. x
