Low power 50x (5x10)
high power 250x (5x50)
If you want to calculate the microscope power of magnification you have to multiple the magnification power of the ocular with the magnification power of the objectiv.
In practice it is enough to simply angle the thermometer towards the direction of the ear canal. More specifically you are trying to target the direction of the tympanic membrane located in the middle ear (one of the parts of the ear; the other parts being outer and inner)
Some maneuvers, although not completely necessary, may include pulling the ear lobe upwards and outwards for babies. This is to straighten the ear canal and is more often done when using otoscopes. For adults, we pull the ear downward and outward.
3rd and 4th awnsers are correct
