i dont get any sound when i connect my laptop to tv using the HDMI wire?

i dont get any sound, i tried restarting, laptop is a dell xps studio 16.
it worked wen i connected it to my uncles tv at his house.
my 2 younger brothers have the same laptop and their one works.
when the tv is connected to the laptop, the computer can reconise the tv as a sound device but when i play something there is no soung.
please help

Answer:

computers Never send sound via HDMI!! the HDMI on computers is officially designated as second monitor not TV usage. as many devices wont allow copy protection to be overwritten so some blu ray or DVD's wont play picture to the TV from laptop over HDMI with 'unauthorised device' errors.

you will need a extra converter to take the sound from the sound output to the TV via sepaerate cable to the phono inputs of the TV or optical if both tv and laptop have them