@Venkatesh GUDEENTI There's just one System Runtime Context, which is used only for background processing. Maybe good to realize it is only used for finding (resolving) the job scheduler and queue processor configurations themselves and are typically not used for executing/running them.
Job Schedulers execute under the access group that you specify in its configuration. Here you also have option to actually have it run under the System Runtime Context, which is maybe not the best choice when you rely on a certain application stack order.
Queue processors are executing in the same access group as was used when queueing the item (unless you explicitly override it with the alternative access group setting)