Question 3

Shown is an apparatus for studying the properties of electrons. Electrons from an emitter F pass through a hole in G and then move into a region where crossed electric (L) and magnetic (M) fields are applied. The spacing between the electric field plates at L is 1 mm. Various target materials can be placed at W. The electrons are detected at a phosphor coated screen labeled x-y. One scale unit on the screen equals 1 cm.

When the crossed electric and magnetic fields are not present, the electron beam hits the screen at point (0,0). When only the permanent magnet M is inserted as shown in the figure, a 1 cm deflection is measured on the screen. Identify the new spot coordinates (x,y).

• A. (1, 0)
• B. (0, 1)
• C. (-1, 0)
• D. (0, -1)
• E. (0, 0)
• F. (0.707, 0.707)
• G. (0.707, -0.707)
• H. (-0.707, 0.707)
• I. (-0.707, -0.707)
• J. None of these

Formula Sheets

Question 2

Question 4

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