  The James Webb Space Telescope near-infrared camera (JWST NIRCam) has two
2.'2 $\times$ 2.'2 fields of view that are capable of either imaging or
spectroscopic observations. Either of two $R \sim 1500$ grisms with orthogonal
dispersion directions can be used for slitless spectroscopy over $\lambda = 2.4
- 5.0$ $\mu$m in each module, and shorter wavelength observations of the same
fields can be obtained simultaneously. We present the latest predicted grism
sensitivities, saturation limits, resolving power, and wavelength coverage
values based on component measurements, instrument tests, and end-to-end
modeling. Short wavelength (0.6 -- 2.3 $\mu$m) imaging observations of the 2.4
-- 5.0 $\mu$m spectroscopic field can be performed in one of several different
filter bands, either in-focus or defocused via weak lenses internal to NIRCam.
Alternatively, the possibility of 1.0 -- 2.0 $\mu$m spectroscopy
(simultaneously with 2.4 -- 5.0 $\mu$m) using dispersed Hartmann sensors (DHSs)
is being explored. The grisms, weak lenses, and DHS elements were included in
NIRCam primarily for wavefront sensing purposes, but all have significant
science applications. Operational considerations including subarray sizes, and
data volume limits are also discussed. Finally, we describe spectral simulation
tools and illustrate potential scientific uses of the grisms by presenting
simulated observations of deep extragalactic fields, galactic dark clouds, and
transiting exoplanets.
