Many varieties of lasers emit light in the form of pulses rather than a steady beam. A tellurium–sapphire laser can produce light at a wavelength of 800 nm in ultrashort pulses that last only 3.75 × 10^−15 s. The energy in a single pulse produced by one such laser is 2.50 × 10^−6 joules, and the pulses propagate in the positive x-direction. Find the: (a) frequency of the light;
(b) energy and minimum energy uncertainty of a single photon in the pulse;
(c) minimum frequency uncertainty of the light in the pulse;
(d) spatial length of the pulse, in meters and as a multiple of the wavelength;
(e) momentum and minimum momentum uncertainty of a single photon in the pulse.

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.