How long should I cook 3 pork chops in the slow cooker?

No.

Just like an oven, the cooking time is often not dependent on the quantity of food.

The only time quantity matters is when you're cooking in the microwave. Time matters with large pieces of meat (roasts, turkeys, etc) simply because the heat has to amke it through to the center of the mass. Pork chops aren't thick enough that you have to adjust for that.

you don't have to put 6chops in you can use 3 if you want....put some diced onion, and carrots perhaps on the bottom of the slow cooker, then the chops ontop*.(i usually put a bit of oil in a fry pan and brown the outsides of the chops or chicken........then put it ontop of the carrots/onions, add some liquid (i usually use dianas bbq sauce mixed with water ) and pour that over* put lid on, turn to low and walk away for about 4-5hrs*. make up some rice or potatoes to go with* and some veggies* you can put the potatoes in the slow cooker to tho if u want*

Enjoy* Im doing a small pork roast today in the slow cooker* I browned all sides of the meat first on the stove then put it ontop of my veggies*

2 hours

Give them the same amount of time as you would for six.

Add a few extra ptatoes and veggies.