You hurl a globe of acid at a distant enemy.
At-Will Acid, Arcane, ImplementStandard Action Ranged 20
Target: One creature
Attack: Charisma vs. Reflex
Hit: 1d10 + Charisma modifier acid damage.Level 21: 2d10 + Charisma modifier acid damage.
Special: This power can be used as a ranged basic attack.So at level 1-20, you would roll 1d10 and add your static modifier. At level 21, you'd roll 2d10 and do the same.Compare this to the sorcerer power ensorcelled blade.
Your blade flashes into action in a painful riposte as your innate magical power flows into it.
At-Will Arcane, Varies, WeaponStandard Action Melee weapon
Requirement: You must be wielding a dagger.
Attack: Charisma vs. AC
Hit: 1[W] + Charisma modifier damage. If the target hits or misses you with a melee attack before the start of your next turn, it takes damage equal to the extra damage from your Spell Source class feature. This damage is of a single type to which you have resistance arising from your Spell Source class feature.Increase damage to 2[W] + Charisma modifier at 21st level.
Special: You can use this power in place of a melee basic attack.Now in this case you roll 1[w], and is must be a dagger (that's a requirement for the power) that would be 1d4, and add your statics mods (2d4+statics at epic).Hope this helps - for implement powers the variance is in the power, for weapon powers the variance is in the type of weapon.