I'm not sure I would use an "Intense" bulb, "flood" bulbs are usually a bit better. A larger basking area is also recommended so there is a range of temps offered to your turtle.
Regarding your question, yes, have the basking light on during the day.
Ones sold under " intense basking spots " are for "some" reptiles and more for amphibians. Not adequate for a RES turtle. As Steve said a "flood" is much better for a slider to thermoregulate itself.