Your coin is modern, Chris. It is worth face value. The same reverse design goes back to 1933, but the portrait changes over the years according to the British Monarch: George V, George VI, and Elizabeth. Some of the early dates carry numismatic (coin collector) value. In fact, if you can find a proof version of this coin, it is worth big bucks: 100s of US dollars. Proof coins are special coins minted solely for collectors; they do not enter circulation.
Circulated coins from this series are worth small amounts: a few dollars at most for all dates. Uncirculated specimens, however, can carry substantial value if old enough. Here is what the catalogs say about this coin when in uncirculated condition:
Before 1956: $50 to $100 catalog value
1956 and after: $2 to $10
If you have one of the early dates of 1933 or 1934, they are worth about $10 in average circulated condition. The 1935 date is slightly scarce, and catalogs at a nice $20 when average circulated, rising to $200 when fully uncirculated. Also if you have one of the dates of 1941 or 1942, they are worth about $40 in average circulated condition and rising to $250 when fully uncirculated.
Use our Important Terminology link to understand what 'catalog value' means.