doubly charged helium atom, whose mass is 6.6×10−27kg, is accelerated by a voltage of 3500 V . 1) What will be its radius of curvature in a uniform 0.280-T field? 2) What is its period of revolution?

An electron with a speed of 5.00E8 cm/s enters an electric eld of magnitude 1.00E3 N/C, traveling along a field line in the direction that retards its motion. (a)  How far will the electron travel in the eld before stopping momentarily? (b)  How much time will have elapsed? (c)  If the region containing the electric eld is 8.00 mm long (too short for the electron to stop within it), what fraction of the electron's initial kinetic energy will be lost in that region?

1. Calculate the solutions to the following question.Two tiny spheres of mass 7.80 mg carry charges of equal magnitude, 72.0 nC, but opposite sign. They are tied to the same ceiling hook by light strings of length 0.530 m. When a horizontal uniform electric field E that is directed to the left is turned on, the spheres hang at rest with the angle θ between the strings equal to 58.0∘.A) Which ball (the one on the right or the one on the left) has positive charge?B) What is the magnitude E of the field? (Don't forget to add units!)

An electric dipole with a dipole moment is inserted in a uniform electric field 35- as in Figure. Due to the torque on the dipole applied by the electric field, the dipole rotates around an axis O perpendicular the plane of the field. Which of the followings is/are true about the dipole? I) Its moment of inertia around the rotation axis is constant. II) Its angular acceleration is constant during the rotation as the magnitudes of and are constant. III) The magnitude of the torque is constant during the rotation as the magnitudes of and are constant.