In a double-slit experiment with a detector at one of the slits, the presence of the detector affects the interference pattern of the electrons. The act of measurement or detection introduces a disturbance to the system, which disrupts the wave-like behavior and alters the resulting pattern.
In a typical double-slit experiment without a detector at the slits, electrons exhibit an interference pattern consisting of alternating bright and dark fringes on a screen behind the slits. This pattern arises from the constructive and destructive interference of the electron waves passing through the two slits.
However, when a detector is placed at one of the slits to determine which slit the electron passes through, the interference pattern is disrupted. The act of measurement collapses the electron's wavefunction, causing it to behave more like a particle with a definite path rather than a superposition of possible paths. This knowledge of the electron's path destroys the interference pattern, resulting in a pattern similar to that observed in a single-slit experiment.
In a single-slit experiment, electrons pass through a single slit and form a diffraction pattern on the screen behind it. The pattern consists of a central maximum and smaller side maxima and exhibits a characteristic distribution of intensity. When a detector is used in a double-slit experiment, the resulting pattern resembles this diffraction pattern of a single slit rather than the interference pattern observed without the detector.
In summary, the presence of a detector at one of the slits in a double-slit experiment alters the resulting interference pattern of electrons. It transforms the pattern into a diffraction-like pattern similar to that observed in a single-slit experiment, as the act of measurement collapses the wavefunction and destroys the interference effects.