Inclusive cross sections for the proton and nuclear targets of A=4, 9, 12, and 16 were measured for 537 and 730 MeV electrons scattered at 37.1 deg. Systematic features of the continuum scattering data are compared with other electron scattering data and with photoabsorption measurements. A model calculation based on the isobar-hole formalism is compared with the data in the delta resonance region.

The inelastic electron-scattering cross sections of H, He, Be, C, and O were measured for 730-MeV electrons scattered at 37.1\ifmmode^\circ\else\textdegree\fi{} for energy transfers to the nucleus up to 550 MeV. The nuclear response in the delta region is found to be quite similar for the $A>1$ targets. Although the differential cross section per nucleon at the peak of the delta region (380 MeV) is suppressed compared to that of the free nucleon, the area in the 230-550-MeV region is enhanced for the $A>1$ targets.

We report measurements of differential cross sections for the reaction $^{4}\mathrm{He}(\ensuremath{\gamma},{\ensuremath{\pi}}^{0})^{4}\mathrm{He}$ with a photon energy of 290 MeV. Use of a good-resolution ${\ensuremath{\pi}}^{0}$ spectrometer allowed restriction of events to those where the residual $^{4}\mathrm{He}$ nucleus was left in the ground state (the coherent process). By detecting the ${\ensuremath{\pi}}^{0}$ directly, we thus provide the first forward-angle data for this reaction in the $\ensuremath{\Delta}$-resonance region. Our results are in good agreement with a recent $\ensuremath{\Delta}$-hole model calculation.

The (${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}, {\ensuremath{\pi}}^{0}$) reactions were studied on targets of $^{12}\mathrm{C}$, $^{14}\mathrm{C}$, $^{16}\mathrm{O}$, and $^{18}\mathrm{O}$ at 160 MeV by measuring the energy spectra of the neutral pions at several laboratory angles between 6\ifmmode^\circ\else\textdegree\fi{} and 160\ifmmode^\circ\else\textdegree\fi{}. The shapes of the energy spectra, the angular distributions, and the ratios of cross sections for isotopic pairs are used to infer the isospin dependence of the $\ensuremath{\Delta}$-nucleus interaction.

Photoproduction of ${\ensuremath{\pi}}^{0}$ mesons off targets of $^{6}\mathrm{Li}$, $^{12}\mathrm{C}$, $^{28}\mathrm{Si}$, $^{40}\mathrm{Ca}$, natural Cd, and natural Pb was studied using a bremsstrahlung beam with endpoint energies of 140, 145, 150, and 155 MeV. Photoproduction from a liquid hydrogen target was employed as a normalization. The measured yields were found to be in disagreement with published theoretical cross sections for $^{6}\mathrm{Li}(\ensuremath{\gamma}, {\ensuremath{\pi}}^{0})^{6}\mathrm{Li}$ and also in disagreement with a simple schematic model which assumed only coherent contributions from the ${M}_{1+}$ multipole. The schematic model, however, did approximately predict the relative magnitudes of the yield curves for the energy range 14-20 MeV over threshold.NUCLEAR REACTIONS $^{6}\mathrm{Li}$, $^{12}\mathrm{C}$, $^{28}\mathrm{Si}$, $^{40}\mathrm{Ca}$, Cd, Pb, ($\ensuremath{\gamma}, {\ensuremath{\pi}}^{0}$); ${E}_{\ensuremath{\gamma}}=140\ensuremath{-}155$ MeV; measured $\ensuremath{\sigma}$; test of reaction model.

The bremsstrahlung yield of the $^{2}\mathrm{H}(\ensuremath{\gamma},{\ensuremath{\pi}}^{+})2n$ reaction is measured from threshold to 25 MeV above threshold. The extracted total cross section relative to the $p(\ensuremath{\gamma},{\ensuremath{\pi}}^{+})n$ cross section is 3-10% greater than the theoretical prediction.NUCLEAR REACTIONS $^{2}\mathrm{H}(\ensuremath{\gamma},{\ensuremath{\pi}}^{+})2n$, bremsstrahlung end point energies to 174 MeV, measured ${\ensuremath{\pi}}^{+}$ yield, deduced $\ensuremath{\sigma}(E)$.

The ${\ensuremath{\pi}}^{+}$ photoproduction on $^{12}\mathrm{C}$ has been measured relative to the proton from 0-20 MeV above threshold. Total cross sections from 0-12 MeV, summed over states in $^{12}\mathrm{B}$ have been extracted with accuracies between 5% and 8% relative to the proton photoproduction cross section. Distorted wave impulse approximation calculations have been performed and show good agreement with the data. The yield from 0-3 MeV above threshold is well described by a one parameter fit for the ground state cross section using only the $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\sigma}}\ifmmode\cdot\else\textperiodcentered\fi{}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\epsilon}}$ term of the Hamiltonian.NUCLEAR REACTIONS $^{12}\mathrm{C}$($\ensuremath{\gamma}$,${\ensuremath{\pi}}^{+}$)$^{12}\mathrm{B}$, bremsstrahlung endpoint energies to 175 MeV, deduced $\ensuremath{\sigma}(E)$; calculated $\ensuremath{\sigma}(E)$, DWIA.