There is no such thing as a 1942 Canadian silver dollar.
The silver content in a 1942 half dollar is approximately 0.3617 ounces of silver. As of recent market prices, which can fluctuate, silver is valued around $24 per ounce. Therefore, the silver in a 1942 half dollar would be worth about $8.68 today. However, keep in mind that numismatic value may exceed this based on collector demand and condition.
The last Peace dollar was issued in 1935 so it can't be a 1942 Peace dollar. Look at the coin again and post new question.
If the coin has any wear the value is for the silver about $12.00
Unless your coin is of some collector value, which would need to be assessed by a coin dealer, a 1942 canadian coin is actually worth more for its silver content value than the 25 cent face value. Your coin contains 80% silver which, at today's prices, is worth approx $2.90 in silver value. The related link below will calculate the value with current silver prices.
Still no 1942 silver dollar US coin. If you mean a 1942 US half dollar it's worth $7.00-$9.00 in circulated condition.
If the coin has any wear the value is for the silver about $12.00
They are worth 4-16 dollars in circulated condition. These coins contain 80% silver!
The coins are valued at a price ranging from $25 to $50. The exact price will depend upon the condition of the coin.
Please check the back of the coin. You'll find that it's a HALF dollar. See the Related Question for more information.
The US didn't print any bills dated 1942. Please check your bill and post a new, separate question.
$455.5
Below a grade of VF-20 Less than a dollar or scrap value, VF+ 1 to 20 dollars. Both silver and nickel 5-cent pieces were made in 1942. The ones that contain silver have a large P or S mint mark over the dome of Monticello.