To answer this question, first you have to see your steem power. Is it more than 500? If no, then you can give only 10 upvotes in 1 day. How?

There are 2 way to upvote, one is you can upvote 100% and another way is you can upvote 1%, 2%, 3% and that % you wanted to vote. If your steem power is less then 500, then you have only one option to upvote, that is you have to upvote 100%.

Steemit gives us 100 energy to vote. When we upvote one person the energy decreases by 2% (for a 100% vote).

Energy calculation:

When you give 1 upvote then your energy will be 98,
for 2nd upvote energy will be 96.04,
for 3rd energy wiil be 94.119,
for 4th energy will be 92.237,
for 5th energy will be 90.39,
for 6th energy will be 88.58,
for 7th energy will be 86.80,
for 8th energy will be 85.06,
for 9th energy will be 83.359,
for 10th energy will be 81.692

Don’t Worry

Don’t worry about your energy. When you are sharing your energy by upvoting, steemit is busy to refill your energy. I mean, to recover one energy it takes 1 hour 18 seconds.
In a day you are sharing 100-81.692=18.308 energy.
So 18.692*1 hour 18 second= almost 23 hours. So if you give 10 upvotes in a day, after 23 hours your energy will be 100. Giving more than 10 upvotes in a day means you use your all energy and also use some steem power, that means your steem power will be decreased.